Moreover, in principle—though he has not yet done so in practice—he could fertilise his somatic-cell-derived eggs with his somatic-cell-derived sperm to create an entirely somatic-cell-derived adult animal.
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Reproductive cloning is accomplished through a technique called somatic cell nuclear transfer.
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In 1996, Dolly became the first animal cloned using a process called somatic cell nuclear transfer.
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The contents of the somatic cell were then implanted into an egg cell that had its nucleus removed.
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And it all began with Dolly the sheep: she was cloned in 1996 using a method called somatic cell nuclear transfer.
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Dolly was the first mammal to be cloned from an adult cell, using a process called somatic cell nuclear transfer (SCNT).
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CRISPR and somatic cell nuclear transfer, for instance, have been used together to create pigs whose organs are safer for human transplantation.
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Furthermore, as had happened before with the somatic-cell-derived sperm, these pups developed normally into adults and were themselves able to reproduce.
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But using this method, called somatic cell nuclear transfer, on humans could be extremely unsafe, because the clone could have serious developmental disorders, Knoepfler says.
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But scientists have learned a lot since developing the technique, and somatic cell nuclear transfer has been used in more than 20 species to make clones.
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In the past, using a slightly different technique from the one that he describes this week, Dr Hayashi has bred mice using somatic-cell-derived sperm.
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The two long-tailed macaques born in December, named Zhong Zhong and Hua Hua, are the first primates to be cloned using somatic cell nuclear transfer, or SCNT.
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Snuppy — named by combining "Seoul National University," where he was born, and the word "puppy" — was produced via somatic cell nuclear transfer, the same technique used to create Dolly the sheep.
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Twenty years after Dolly became the first mammal ever to be cloned, this is the first research aimed at investigating healthy ageing in clones made by somatic cell nuclear transfer, or SCNT.
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It was achieved through a process called somatic cell nuclear transfer (SCNT), which involves transferring the nucleus of a cell, which includes its DNA, into an egg which has had its nucleus removed.
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Though somatic cell nuclear transfer has been used in humans, it has been performed only to generate stem cells, Sinclair said, adding that "there's nobody out there interested in generating clones of humans."
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Primates have been cloned before, but this is the first time monkeys were duplicated using the same technique — called somatic cell nuclear transfer —that scientists used to clone Dolly the sheep, in 1996.
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Regardless of poor efficiency and a fuzzy understanding, somatic cell nuclear transfer has been undertaken in more than 20 species of mammals to create clones, according to Kenneth Sinclair, lead author of the new study.
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Researchers at the Chinese Academy of Sciences Institute of Neuroscience in Shanghai used a process called somatic cell nuclear transfer to transfer the nucleus of a cell into an egg which had its nucleus removed.
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According to Feng, Longlong's birth was the first time scientists had combined two cutting-edge bio-technologies: A gene-editing tool called CRISPR with somatic cell cloning technology - the method used to clone Dolly the sheep.
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The process scientists used to clone the D-squad and other animals — somatic cell nuclear transfer — involves wiping out existing DNA in an egg cell and replacing it with new DNA, which isn't always a clean sweep.
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These monkeys are the first primates to be cloned using a technique called somatic cell nuclear transfer (SCNT), the same method that was used to create the first animal clone, Dolly the sheep, over 20 years ago.
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In the case of Hua Hua and Zhong Zhong, researchers used modern technology developed only in the last couple of years to enhance the technique used to clone Dolly, which is called somatic cell transfer, or SCNT.
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A team of researchers at Nottingham University announced on Tuesday that four of Dolly the Sheep's genetic identicals are showing no signs of premature aging—evidence that "somatic cell nuclear transfer," or cloning, can result in healthy adult mammals.
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"The program also plans to establish a somatic cell bank of good-performing police dogs that can be preserved for 50 years and a group of good-performing police dogs for breeding to fast breed good police dogs."Er. Cool.
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The National Institutes of Health's new Somatic Cell Genome Editing will award funds over six years to researchers working to solve problems that will help accelerate research across the field, like developing better delivery mechanisms or better methods for gene editing.
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The controversial experiment was the first time a primate has been successfully cloned using a technique known as somatic cell nuclear transfer — the same technique used to clone Dolly the sheep two decades earlier (it's much harder to do on primates).
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How they did it: In somatic cell nuclear transfer cloning, DNA from the cell of the individual being cloned is transferred into an unfertilized egg, which is then placed in a surrogate mother to develop into a clone of the donor.
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Scientists have already used cloning to restore, for a few brief minutes, the Pyrenean ibex, a method that relies on using the nucleus of the somatic cell of an extinct species and transferring it into the germ cell of a host species.
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Using a breakthrough technique called somatic cell nuclear transfer, scientists at Roslin took a nucleus -- the part of the cell that contains most of its genetic information -- from cells within the mammary gland of an adult sheep and stuck it inside an unfertilized egg from which the nucleus had been removed.
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Milk from cows with mastitis also has a higher somatic cell count. Generally speaking, the higher the somatic cell count, the lower the milk quality.
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Milk from cows with mastitis also has a higher somatic cell count. Generally speaking, the higher the somatic cell count, the lower the milk quality.
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The process of somatic cell nuclear transplant involves two different cells. The first being a female gamete, known as the ovum (egg/oocyte). In human SCNT (Somatic Cell Nuclear Transfer) experiments, these eggs are obtained through consenting donors, utilizing ovarian stimulation. The second being a somatic cell, referring to the cells of the human body.
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Somatic Cell and Molecular Genetics is fully indexed in Index Medicus, MEDLINE, and PubMed.
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Also, Rex1−/Oct3/4+ cells differentiate into cells of primitive ectoderm, the somatic cell lineage.
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Diagram of SCNT Process In somatic cell nuclear transfer ("SCNT"), the nucleus of a somatic cell is taken from a donor and transplanted into a host egg cell, which had its own genetic material removed previously, making it an enucleated egg. After the donor somatic cell genetic material is transferred into the host oocyte with a micropipette, the somatic cell genetic material is fused with the egg using an electric current. Once the two cells have fused, the new cell can be permitted to grow in a surrogate or artificially. This is the process that was used to successfully clone Dolly the sheep (see section on History in this article).
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An oocyte can reprogram an adult nucleus into an embryonic state after somatic cell nuclear transfer, so that a new organism can be developed from such cell. Reprogramming is distinct from development of a somatic epitype, as somatic epitypes can potentially be altered after an organism has left the developmental stage of life. During somatic cell nuclear transfer, the oocyte turns off tissue specific genes in the Somatic cell nucleus and turns back on embryonic specific genes.
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Skin cells, fat cells, and liver cells are only a few examples. The genetic material of the donor egg cell is removed and discarded, leaving it 'deprogrammed.' What is left is a somatic cell and an enucleated egg cell. These are then fused by inserting the somatic cell into the 'empty' ovum.
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Center for Biologics Evaluation and Research. Guidance for Industry: Guidance for Human Somatic Cell Therapy and Gene Therapy. March 1998.
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The altered phenotype observed in GDF9 deficient oocytes likely results from the lack off somatic cell input in later stages of folliculogenesis.
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Dolly the sheep, the first mammal successfully cloned from an adult somatic cell, was euthanized after it was confirmed that she had OPA.
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Cloning also might be done with stem cells. Pluripotent stem cells can also be derived from Somatic cell nuclear transfer which is a laboratory technique where a clone embryo is created from a donor nucleus. Somatic cell nuclear transfer is also tightly regulated amongst various countries. Until recently, the principal source of human embryonic stem cells has been donated embryos from fertility clinics.
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S. 1758 'Human Cloning Prohibition Act of 2001'. Accessed November 30, 2006 which would allow somatic cell nuclear transfer research, but would ban reproductive cloning. He argued that stem cell implantation is unsafe unless the stem cells contain the patient's own DNA and that because somatic cell nuclear transfer is done without fertilizing an egg, it can be fully regulated.Christopher Reeve Homepage.
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This causes the cell lineage and cell fate to be highly correlated. Other organisms, such as humans, have variable lineages and somatic cell numbers.
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28 Nov 2013. In 1962, John B. Gurdon demonstrated that the nucleus from a differentiated frog intestinal epithelial cell can generate a fully functional tadpole via transplantation to an enucleated egg. Gurdon used somatic cell nuclear transfer (SCNT) as a method to understand reprogramming and how cells change in specialization. He concluded that differentiated somatic cell nuclei had the potential to revert to pluripotency.
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The SCC is quantified as cells per milliliter. General agreement rests on a reference range of less than 100,000 cells/mL for uninfected cows and greater than 250,000 for cows infected with significant pathogen levels. Several tests like the PortaSCC milk test and The California mastitis test provide a cow-side measure of somatic cell count. The somatic cell count in the milk also increases after calving when colostrum is produced.
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If it's a natural duplication, it can still take place in a somatic cell, rather than a germline cell (which would be necessary for a lasting evolutionary change).
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Dolly (5 July 1996 – 14 February 2003) was a female domestic sheep, and the first mammal cloned from an adult somatic cell, using the process of nuclear transfer.
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Somatic Cell and Molecular Genetics was a peer-reviewed scientific journal in the fields of cell biology and molecular genetics. The journal was established in 1975 as Somatic Cell Genetics. The founding editor-in-chief was Richard L. Davidson (then of the University of Illinois College of Medicine). The journal expanded scope to encompass the increased development of molecular genetics and changed its name to reflect this with the tenth volume January 1984 edition.
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This phenomenon is called X-inactivation or Lyonization, and creates a Barr body. If X-inactivation in the somatic cell meant a complete de-functionalizing of one of the X-chromosomes, it would ensure that females, like males, had only one functional copy of the X chromosome in each somatic cell. This was previously assumed to be the case. However, recent research suggests that the Barr body may be more biologically active than was previously supposed.
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The five cloned embryos, created in Stemagen Corporation lab in La Jolla, were later destroyed. Wood and five other researchers published their findings in the online research journal Stem Cells in an article entitled Development of Human cloned Blastocyst Following Somatic Cell Nuclear Transfer (SCNT) with Adult Fibroblasts.French, Andrew J., Cathrine A. Adams et al. Development of Human cloned Blastocyst Following Somatic Cell Nuclear Transfer (SCNT) with Adult Fibroblasts Stem Cells published by AlphaMed Press January 17, 2008.
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Somatic cell nuclear transfer is a technique for cloning in which the nucleus of a somatic cell is transferred to the cytoplasm of an enucleated egg. When this is done, the cytoplasmic factors affect the nucleus to become a zygote. The blastocyst stage is developed by the egg which helps to create embryonic stem cells from the inner cell mass of the blastocyst. The first animal that was developed by this technique was Dolly, the sheep, in 1996.
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The human gastrointestinal tract is colonized by a vast community of symbionts and commensals. The researchers demonstrate the phenomenon of somatic cell reprograming by bacteria and generation of multipotential cells from adult human dermal fibroblast cells by incorporating Lactic acid bacteria This cellular transdifferentiation is caused by ribosomes and "can occur via donor bacteria that are swallowed and digested by host cells, which may induce ribosomal stress and stimulate cellular developmental plasticity". Ribosomes Found to Induce Somatic Cell Pluripotency. Technology Networks.
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This process can either add or delete specific genomes of farm animals. A key point to remember is that cloning is achieved when the oocyte maintains its normal functions and instead of using sperm and egg genomes to replicate, the oocyte is inserted into the donor's somatic cell nucleus. The oocyte will react on the somatic cell nucleus, the same way it would on sperm cells. The process of cloning a particular farm animal using SCNT is relatively the same for all animals.
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Somatic cell nuclear transfer can create clones for both reproductive and therapeutic purposes. The diagram depicts the removal of the donor nucleus for schematic purposes; in practice the whole donor cell is transferred. In genetics and developmental biology, somatic cell nuclear transfer (SCNT) is a laboratory strategy for creating a viable embryo from a body cell and an egg cell. The technique consists of taking an enucleated oocyte (egg cell) and implanting a donor nucleus from a somatic (body) cell.
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When she moved the somatic cell to a different place, germ cells started dividing in that new location. This was the first time a single cell with such an oversight function had been identified.
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Zhang K, et al. Nat. Genet. 2006;38:382–87 sperm typing, bacterial artificial chromosome cloning, construction of somatic cell hybrids, atomic force microscopy, among others. Haplotype phasing can also be achieved through computational inference methods.
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In recent years, the technique of cloning whole organisms has been developed in mammals, allowing almost identical genetic clones of an animal to be produced. One method of doing this is called "somatic cell nuclear transfer" and involves removing the nucleus from a somatic cell, usually a skin cell. This nucleus contains all of the genetic information needed to produce the organism it was removed from. This nucleus is then injected into an ovum of the same species which has had its own genetic material removed.
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Somatic cell nuclear transfer can create clones for both reproductive and therapeutic purposes. The diagram depicts the removal of the donor nucleus for schematic purposes; in practice the whole donor cell is transferred. In the late 1990s, the method that scientists used in cloning was somatic cell nuclear transfer, which is the same procedure that was used to create Dolly the sheep. This laboratory technique begins when an egg is taken from a donor and the nucleus is removed from the egg, creating an enucleated egg.
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Somatic Cell Nuclear Transfer (SCNT) is the process by which the nucleus of an oocyte (egg cell) is removed and is replaced with the nucleus of a somatic (body) cell (examples include skin, heart, or nerve cell). The two entities fuse to become one and factors in the oocyte cause the somatic nucleus to reprogram to a pluripotent state. The cell contains genetic information identical to the donated somatic cell. After stimulating this cell to begin dividing, in the proper conditions an embryo will develop.
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Reproductive cloning generally uses "somatic cell nuclear transfer" (SCNT) to create animals that are genetically identical. This process entails the transfer of a nucleus from a donor adult cell (somatic cell) to an egg from which the nucleus has been removed, or to a cell from a blastocyst from which the nucleus has been removed. If the egg begins to divide normally it is transferred into the uterus of the surrogate mother. Such clones are not strictly identical since the somatic cells may contain mutations in their nuclear DNA.
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It is a characteristic that would not be observed naturally in a specimen. The term mutant is also applied to a virus with an alteration in its nucleotide sequence whose genome is RNA, rather than DNA. In multicellular eukaryotes, a DNA sequence may be altered in an individual somatic cell that then gives rise to a mutant somatic cell lineage as happens in cancer progression. Also in eukaryotes, alteration of a mitochondrial or plastid DNA sequence may give rise to a mutant lineage that is inherited separately from mutant genotypes in the nuclear genome.
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Two common methods of therapeutic cloning that are being researched are somatic-cell nuclear transfer and, more recently, pluripotent stem cell induction. Reproductive cloning would involve making an entire cloned human, instead of just specific cells or tissues.
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Samuel H. Wood is a scientist and fertility specialist. In 2008, he became the first man to clone himself, donating his own DNA via somatic cell nuclear transfer (SCNT) to produce mature human embryos that were his clones.
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The resulting cloned animal is an exact genetic replica of the adult mammal from which the somatic cell nucleus was taken.750 F.3d at 1334. The patent application claims the cloned animal. Claim 155 is representative: : 155\.
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Two common methods of therapeutic cloning that are being researched are somatic-cell nuclear transfer and (more recently) pluripotent stem cell induction. Reproductive cloning would involve making an entire cloned human, instead of just specific cells or tissues.
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Such single gene disorders are good candidates for somatic cell therapy. The complete correction of a genetic disorder or the replacement of multiple genes is not yet possible. Only a few of the trials are in the advanced stages.
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French, Andrew J., Cathrine A. Adams et al. Development of human cloned blastocysts following somatic cell nuclear transfer (SCNT) with adult fibroblasts Stem Cells published by AlphaMed Press 2008 Feb;26(2):485-93. Epub 2008 January 17, 2008.
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In January 2018, scientists in China reported in the journal Cell the first creation of two crab-eating macaque clones, named Zhong Zhong and Hua Hua, using somatic cell nuclear transfer – the same method that produced Dolly the sheep.
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Polly and Molly (born 1997), two ewes, were the first mammals to have been successfully cloned from an adult somatic cell and to be transgenic animals at the same time. This is not to be confused with Dolly the Sheep, the first animal to be successfully cloned from an adult somatic cell where there wasn’t modification carried out on the adult donor nucleus. Polly and Molly, like Dolly the Sheep, were cloned at the Roslin Institute in Edinburgh, Scotland. The creation of Polly and Molly built on the somatic nuclear transfer experiments that led to the cloning of Dolly the Sheep.
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The cloning method Campbell and Wilmut used to create Dolly constituted a breakthrough in scientific discovery. Known as somatic cell nuclear transfer, this process involves removing the nucleus of a regular body cell and implanting that nucleus into an egg cell that has had its cell nucleus removed. A nucleus is the organelle that holds a cell's genetic material (its DNA). Campbell and Wilmut found that if the donor, somatic cell is arrested in the stage of the cell cycle where it is dormant and non-replicating (the quiescent phase) prior to nuclear transfer, the resulting fused cell will develop into an embryo.
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The Finnish Dorset named Dolly is exhibited at the Royal Museum of Scotland.A Finnish Dorset is a crossed-breed sheep, half Finnsheep, and half Dorset breed. Dolly the sheep, first mammal to be cloned from an adult somatic cell, was a Finnish Dorset.
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Any somatic cell formation after the primary layer is atypical and asymmetrical. Normally the follicle becomes atretic and degenerates although this does not occur emphasizing the abnormality of these supporting cells. GDF9 deficiency is further linked with the up regulation of inhibin.
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Pig oocyte surrounded by granulosa cells. Fluorescence microscopy, colored with DAPI. A granulosa cell or follicular cell is a somatic cell of the sex cord that is closely associated with the developing female gamete (called an oocyte or egg) in the ovary of mammals.
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Chk1 impacts various stages of the cell cycle including the S phase, G2/M transition and M phase. In addition to mediating cell cycle checkpoints, Chk1 also contributes to DNA repair processes, gene transcription, embryo development, cellular responses to HIV infection and somatic cell viability.
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Transdifferentiation, also known as lineage reprogramming, is an artificial process in which one mature somatic cell is transformed into another mature somatic cell without undergoing an intermediate pluripotent state or progenitor cell type. It is a type of metaplasia, which includes all cell fate switches, including the interconversion of stem cells. Current uses of transdifferentiation include disease modeling and drug discovery and in the future may include gene therapy and regenerative medicine. The term 'transdifferentiation' was originally coined by Selman and Kafatos in 1974 to describe a change in cell properties as cuticle producing cells became salt- secreting cells in silk moths undergoing metamorphosis.
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KMT2D facilitates cell fate transition by priming enhancers (through H3K4me1) for p300-mediated activation. For p300 to bind the enhancer, the physical presence of KMT2D, and not just the KMT2D-mediated H3K4me1, is required. However, KMT2D is dispensable for maintaining embryonic stem cell and somatic cell identity.
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Oyalı (21 November 2007 - 16 April 2012) was a sheep who was the first cloned animal in Turkey. Oyalı was successfully cloned from an adult somatic cell. She was cloned by Prof. Dr. Sema Birler and colleagues in November 2007 in Istanbul University in Istanbul, Turkey.
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The Committee for Advanced Therapies (CAT) was established in accordance with Regulation (EC) No 1394/2007 on advanced-therapy medicinal products (ATMPs) such as gene therapy, somatic cell therapy and tissue engineered products. It assesses the quality, safety and efficacy of ATMPs, and follows scientific developments in the field.
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Scientists are making progress in their efforts to bring the gastric-brooding frog species back to life using somatic-cell nuclear transfer (SCNT), a method of cloning.Nosowitz, Dan (15 March 2013) Scientists Resurrect Bonkers Extinct Frog That Gives Birth Through Its Mouth. popsci.com In March 2013, Australian scientists successfully created a living embryo from non-living preserved genetic material. These scientists from the University of Newcastle Australia led by Prof Michael Mahony, who was the scientist who first discovered the northern gastric-brooding frog, Simon Clulow and Prof Mike Archer from the University of New South Wales hope to continue using somatic-cell nuclear transfer methods to produce an embryo that can survive to the tadpole stage.
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Hossein MS, Jeong YW, Park SW, Kim JJ, Lee E, Ko KH, Kim HS, Kim YW, Hyun SH, Shin T, Hawthorne L, Hwang WS.Cloning missy: obtaining multiple offspring of a specific canine genotype by somatic cell nuclear transfer. Cloning Stem Cells. 2009 Mar;11(1):123-30. doi: 10.1089/clo.2008.0029.
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Developmental effects have been associated with pesticides. Recent increases in childhood cancers in throughout North America, such as leukemia, may be a result of somatic cell mutations. Insecticides targeted to disrupt insects can have harmful effects on mammalian nervous systems. Both chronic and acute alterations have been observed in exposes.
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In some multicellular groups, which are called Weismannists, a separation between a sterile somatic cell line and a germ cell line evolved. However, Weismannist development is relatively rare (e.g., vertebrates, arthropods, Volvox), as a great part of species have the capacity for somatic embryogenesis (e.g., land plants, most algae, many invertebrates).
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ViaGen's subsidiary, Start Licensing, owns a cloning patent which is licensed to their only competitor as of 2018, who also offers animal cloning services. The cloning process used by both ViaGen and their competitor is somatic cell nuclear transfer, the same as which was used for cloning Dolly the Sheep.
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Fusion of two cells produces a heterokaryon, i.e., a single hybrid cell with two nuclei, one from each of the cells entering fusion. Subsequently, the two nuclei also fuse to yield a hybrid cell with a single nucleus. A generalized scheme for somatic cell hybridization may be described as follows.
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Retrieved April 8, 2009. Stem cell treatments are a type of cell therapy that introduce new cells into adult bodies for possible treatment of cancer, somatic cell nuclear transfer, diabetes, and other medical conditions. Cloning also might be done with stem cells. Stem cells have been used to repair tissue damaged by disease.
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The court stated that milk from rBGH-treated cows has: increased levels of the hormone Insulin-like growth factor 1 (IGF-1); higher fat content and lower protein content when produced at certain points in the cow's lactation cycle; and more somatic cell counts, which may "make the milk turn sour more quickly".
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Transflamation describes the process by which innate immune response mechanisms affect the epigenetic plasticity of a cell during nuclear reprogramming. This phenomenon is essential in dedifferentiating a somatic cell to a pluripotent cell (induction of an induced pluripotent stem cell, iPSC) and also in transdifferentiating a terminally differentiated cell to another terminally differentiated cell.
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GM sperm is not frequently used in humans but has been extensively tested and studied in animals. This type of modification of the sperm, eggs, or early embryos is known as an Inheritable Genetic Modification. Because the genetic changes are passed onto future generations, Inheritable Genetic Modification is far more consequential than somatic cell modifications.
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In re Roslin Institute (Edinburgh), 750 F.3d 1333 (Fed. Cir. 2014), is a 2014 decision of the United States Court of Appeals for the Federal Circuit rejecting a patent for a cloned sheep known as "Dolly the Sheep"— the first mammal ever cloned from an adult somatic cell.750 F.3d at 1334.
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This was the first time an intact differentiated somatic cell could be reprogrammed to become pluripotent. This opened up a completely new research field. In July 2014, a scandal regarding the research of Haruko Obokata was connected to Yamanaka. He could not find the lab notes from the period in question and was made to apologise.
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Cloning would involve removal of the DNA-containing nucleus of the egg cell of a female elephant, and replacement with a nucleus from woolly mammoth tissue, a process called somatic cell nuclear transfer. For example, Akira Iritani, at the Kyoto University in Japan, reportedly planned to do this.Scientists trying to clone, resurrect extinct mammoth . Brad Lendon.
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On 24 January 2018, scientists in China reported in the journal Cell the creation of two crab- eating macaque clones, named Zhong Zhong and Hua Hua, using the complex DNA transfer method that produced Dolly the sheep. This makes Zhong Zhong and Hua Hua the first primates to be cloned using the somatic cell nuclear transfer method.
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McCarthy and O'Callaghan are second-year students at Kinsale Community School in County Cork. They come from a background of dairy farming. Their project at the exhibition was titled "'The Development of a Convenient Test Method for Somatic Cell Count and Its Importance in Milk Production". Their intention was to mix detergent with milk to reduce somatic cells.
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Additionally, EBs can be formed from embryonic stem cells derived through alternative techniques, including somatic cell nuclear transfer or the reprogramming of somatic cells to yield induced pluripotent stem cells (iPS). Similar to ESCs cultured in monolayer formats, ESCs within embryoid bodies undergo differentiation and cell specification along the three germ lineages – endoderm, ectoderm, and mesoderm – which comprise all somatic cell types. In contrast to monolayer cultures, however, the spheroid structures that are formed when ESCs aggregate enables the non-adherent culture of EBs in suspension, making EB cultures inherently scalable, which is useful for bioprocessing approaches, whereby large yields of cells can be produced for potential clinical applications. Additionally, although EBs largely exhibit heterogeneous patterns of differentiated cell types, ESCs are capable of responding to similar cues that direct embryonic development.
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The grouped somatic cell and egg cytoplasm are then introduced to an electrical current. This energy will hopefully allow the cloned embryo to begin development. The successfully developed embryos are then placed in surrogate recipients, such as a cow or sheep in the case of farm animals. SCNT is seen as a good method for producing agriculture animals for food consumption.
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Lippincott Williams & Wilkins, . In February 1997 a team at the Roslin Institute in Scotland announced the birth of Dolly the sheep, the first mammal to be cloned from an adult somatic cell. Concerns have been raised over the mistreatment of primates undergoing testing. In 1985 the case of Britches, a macaque monkey at the University of California, Riverside, gained public attention.
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Vajta is one of several co- developers of handmade cloning (HMC)."Cell Nuclear Transfer" patent no. US20090119787 HMC is a radical technical modification of Somatic cell nuclear transfer of the original mammalian nuclear transfer technology established by Willadsen and applied for somatic cells by Wilmut and Campbell. The technique does not require micromanipulators only a simple stereomicroscope and an inexpensive fusion machine.
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Tail docking of dairy cows is prevalent in some regions. Some anecdotal reports have suggested that such docking may reduce SCC (somatic cell counts in milk) and occurrence of mastitis. However, a study examining such issues found no significant effect of docking on SCC or mastitis frequency or on four measures of cow cleanliness.Tucker, C. B., D. Fraser and D. M. Weary. 2001.
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Somatic cell nuclear transplantation has become a focus of study in stem cell research. The aim of carrying out this procedure is to obtain pluripotent cells from a cloned embryo. These cells genetically matched the donor organism from which they came. This gives them the ability to create patient specific pluripotent cells, which could then be used in therapies or disease research.
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These ligands are secreted into the GSCs from the SSCs and hub cells, activate BMP signalling, and suppress the expression of Bam, a differentiation factor. Outside of the niche, gonialblasts no longer receive BMP ligands, and are free to begin their differentiation program. Other important signalling pathways include the MAPK and Hedgehog, which regulate germline enclosure and somatic cell self-renewal, respectively.
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A somatic cell (from Ancient Greek σῶμα sôma, meaning "body"), or vegetal cell, is any biological cell forming the body of an organism; that is, in a multicellular organism, any cell other than a gamete, germ cell, gametocyte or undifferentiated stem cell. In contrast, gametes are cells that fuse during sexual reproduction, germ cells are cells that give rise to gametes, and stem cells are cells that can divide through mitosis and differentiate into diverse specialized cell types. For example, in mammals, somatic cells make up all the internal organs, skin, bones, blood and connective tissue, while mammalian germ cells give rise to spermatozoa and ova which fuse during fertilization to produce a cell called a zygote, which divides and differentiates into the cells of an embryo. There are approximately 220 types of somatic cell in the human body.
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Protein percentage: 4.05%. Breeding objectives for the year 2020 also look at conformation on the Danish Jersey. Focus is being put on increasing height and weight at maturity as well as strong feet and legs, udder strength and depth, and udder and teat shape. Other traits such as lowering somatic cell count (below 200,000), decreasing treatment with antibiotics, longevity (minimum 3 lactations), and increased fertility.
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Uniformity is a general requirement of cultivated line in most species, which can be easily obtained through DH production.International Symposium on Genetic Manipulation in Crops. 1988. Genetic manipulation in crops proceedings of the International Symposium on Genetic Manipulation in Crops, the 3rd International Symposium on Haploidy, the 1st International Symposium on Somatic Cell Genetics in Crops, Beijing, October 1984. Natural resources and the environment series, v. 22.
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Professor Tischfield obtained his bachelor's degree in biology in 1967 at the City University of New York, Brooklyn College. He finished his master's degree in biology at Yale University in 1969, where he received his PhD in 1973. At Yale, Tischfield worked on mapping human genes to chromosomes. He used mice-man somatic cell hybrids to determine which genes are located on which chromosomes.
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In another opinion piece he urged support for somatic cell nuclear transfer (sometimes known as 'therapeutic cloning'). He continued to advocate nature conservation, for example by calling for national park declarations over the River Red Gums. He wrote in 2009 that the river red gums are "Australian icons, part of our folklore, symbols of inland Australia". He was an opponent of a charter of rights.
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His doctoral dissertation was entitled "Bloom syndrome as a human mutator mutation". He published 12 manuscripts during his doctoral training. Warren's postdoctoral studies were focused on human molecular genetics and he first began his studies on fragile X syndrome. He made somatic cell hybrids isolating the human fragile X chromosome in rodent cells and devised a strategy to molecular clone the DNA responsible for the syndrome.
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Blunt signed bills to expand Missouri's right-to-carry firearms. At the NRA's annual meeting, held in St. Louis in 2007, Blunt signed legislation prohibiting the seizure of firearms during declared states of emergency. Blunt opposed abortion except in cases of rape, incest, and to save the life of the mother.Ontheissues.org - Matt Blunt He supported measures to prevent the ban on research regarding somatic cell nuclear transfer.
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The selection of tag SNPs is dependent on the haplotypes present in the genome. Most sequencing technologies provide the genotypic information and not the haplotypes i.e. they provide information on the specific bases that are present but do not provide phasic information (at which specific chromosome each of the bases appear). Determination of haplotypes can be done through molecular methods (Allele Specific PCR, Somatic cell hybrids).
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Using MII oocytes from volunteers and their improved SCNT procedure, human clone embryos were successfully produced. These embryos were of poor quality, lacking a substantial inner cell mass and poorly constructed trophectoderm. The imperfect embryos prevented the acquisition of human ESC. The addition of caffeine during the removal of the ovum's nucleus and fusion of the somatic cell and the egg improved blastocyst formation and ESC isolation.
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An example of upregulation is the response of liver cells exposed to such xenobiotic molecules as dioxin. In this situation, the cells increase their production of cytochrome P450 enzymes, which in turn increases degradation of these molecules. Downregulation or upregulation of an RNA or protein may also arise by an epigenetic alteration. An epigenetic alteration can be permanent or semi-permanent in a somatic cell lineage.
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Norwegian Red cows had a lower somatic cell score than HF cows during all lactations. Conception rates to first artificial insemination were higher with the NR cows during lactations 1 to 4 (57.8 vs 40.9%, respectively), with 28.5% of HF cows and 11.8% of NR cows culled as infertile before lactation 6. In general, NR cows outperformed HF cows in traits that have been historically included in the NR breeding program.
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Physical mapping uses DNA fragments and DNA markers to assemble larger DNA pieces. With the overlapping regions of the fragments, researchers can deduce the positions of the DNA bases. There are different techniques to visualize the gene location, including somatic cell hybridization, radiation hybridization and in situ hybridization. The different approaches to physical mapping are available for analyzing different sizes of genome and achieving different levels of accuracy.
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All work is done by hand, with simple handheld tools (blade and micropipette). The first cloned animals in Africa"Futi on BBC” and Scandinavia"Danish piglets” were both produced by HMC. Transgenic pigs as models for various human diseases were produced with putative genes responsible for Parkinson's and Alzheimer's disease, Psoriasis, Arteriosclerosis and Diabetes mellitus. The technology promises a new possibility for automation of the somatic cell nuclear transfer procedure.
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Stem-cell therapy has become controversial following developments such as the ability of scientists to isolate and culture embryonic stem cells, to create stem cells using somatic cell nuclear transfer and their use of techniques to create induced pluripotent stem cells. This controversy is often related to abortion politics and to human cloning. Additionally, efforts to market treatments based on transplant of stored umbilical cord blood have been controversial.
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These findings have been published in Nature in 2009. With this method, Knoblich could further elucidate brain tumor development in fruit flies. Recent findings suggest that tumors can be based on stem cells, that keep their unique stem cell characteristics and thus uncontrollably divide, without ever differentiating into specific somatic cell types. This lack of differentiation is caused by Brat, a gene that has been identified by Knoblich and his team.
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Unlike true stem cells, callus is heterogeneous. Due to this reason, continuous and stable cell division of callus is difficult. Hence a plant stem cell originated from cambium is an immortal cell while that from callus is a temporarily dediffertiated cell obtained from stimulating the somatic cell. Furthermore, the ability to differentiate and proliferate is different that differences between plant stem cell and callus are prevalent in culture and research.
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C-value is the amount, in picograms, of DNA contained within a haploid nucleus (e.g. a gamete) or one half the amount in a diploid somatic cell of a eukaryotic organism. In some cases (notably among diploid organisms), the terms C-value and genome size are used interchangeably; however, in polyploids the C-value may represent two or more genomes contained within the same nucleus. Greilhuber et al.
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In cattle, GBS causes mastitis, an infection of the udder. It can produce an acute febrile disease or a subacute, more chronic disease. Both lead to diminishing milk production (hence its name: agalactiae meaning "no milk"). Mastitis associated with GBS can have an important effect on the quantity and quality of milk produced, and is also associated with elevated somatic cell count and total bacteria count in the milk.
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The key to their success was utilizing oocytes in metaphase II (MII) of the cell cycle. Egg cells in MII contain special factors in the cytoplasm that have a special ability in reprogramming implanted somatic cell nuclei into cells with pluripotent states. When the ovum's nucleus is removed, the cell loses its genetic information. This has been blamed for why enucleated eggs are hampered in their reprogramming ability.
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Pet cloning is the cloning of a pet animal. One common way in which an animal is cloned is by somatic cell nuclear transfer. In this process an oocyte is taken from a surrogate mother and put through a process called enucleation, which removes the nucleus from inside oocyte. Somatic cells are then taken from the animal that is being cloned, transferred into the blank oocyte and fused using an electrical current.
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Like all cells, somatic cells contain DNA arranged in chromosomes. If a somatic cell contains chromosomes arranged in pairs, it is called diploid and the organism is called a diploid organism. (The gametes of diploid organisms contain only single unpaired chromosomes and are called haploid.) Each pair of chromosomes comprises one chromosome inherited from the father and one inherited from the mother. For example, in humans, somatic cells contain 46 chromosomes organized into 23 pairs.
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Megan and Morag, two domestic sheep, were the first mammals to have been successfully cloned from differentiated cells. They are not to be confused with Dolly the sheep which was the first animal to be successfully cloned from an adult somatic cell or Polly the sheep which was the first cloned and transgenic animal. Megan and Morag, like Dolly and Polly, were cloned at the Roslin Institute in Edinburgh, Scotland in 1995.
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A plastic paddle used in the California mastitis test. Cattle affected by mastitis can be detected by examining the udder for inflammation and swelling, or by observing the consistency of the milk, which will often develop clots or change color when a cow is infected. Another method of detection is the California mastitis test, which is designed to measure the milk's somatic cell count as a means for detecting inflammation and infection of the udder.
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In 2000, Robert Lanza was able to produce a cloned fetus of a gaur, Bos gaurus, combining it successfully with a domestic cow, Bos taurus. Interspecies nuclear transfer provides evidence of the universality of the triggering mechanism of the cell nucleus reprogramming. For example, Gupta et al., explored the possibility of producing transgenic cloned embryos by interspecies somatic cell nuclear transfer (iSCNT) of cattle, mice, and chicken donor cells into enucleated pig oocytes.
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But the cell has an enzyme called telomerase, which carries out the task of adding repetitive nucleotide sequences to the ends of the DNA. Telomerase "replenishes" the telomere "cap." In most multicellular eukaryotic organisms, telomerase is active only in germ cells, some types of stem cells such as embryonic stem cells, and certain white blood cells. Telomerase can be reactivated and telomeres reset back to an embryonic state by somatic cell nuclear transfer.
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Such cells were transplanted into the liver and kidney of mice and found became indistinguishable from existing endothelial cells. In a clinical setting the cells must be immunocompatible with the recipient patient. They could be derived from the patient's embryonic pluripotent stem cells as well as by somatic cell nuclear transfer (SCNT). In SCNT the nucleus is introduced into a human egg producing embryonic stem cells that are a genetic match of the patient.
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Somatic-cell nuclear transfer, popularly known as SCNT, can also be used to create embryos for research or therapeutic purposes. The most likely purpose for this is to produce embryos for use in stem cell research. This process is also called "research cloning" or "therapeutic cloning". The goal is not to create cloned human beings (called "reproductive cloning"), but rather to harvest stem cells that can be used to study human development and to potentially treat disease.
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Commercially relevant bioprocesses will: # Produce products that maintain all of the quality standards of biopharmaceutical drugsDraft Guidance : Instructions and Template for CMC Reviewers of Human Somatic Cell Therapy IND Applications # Supply both clinical and commercial quantities of therapeutic cells throughout the various stages of development. The processes and production technologies must be scalable, and # Control the cost of goods (CoGs) of the final drug product. This aspect is critical to building the foundation for a commercially viable industry.
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Differentiated somatic cells and ES cells use different strategies for dealing with DNA damage. For instance, human foreskin fibroblasts, one type of somatic cell, use non-homologous end joining (NHEJ), an error prone DNA repair process, as the primary pathway for repairing double-strand breaks (DSBs) during all cell cycle stages. Because of its error-prone nature, NHEJ tends to produce mutations in a cell’s clonal descendants. ES cells use a different strategy to deal with DSBs.
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A graphical representation of the standard human karyotype, including both the male (XY) and female (XX) sex chromosomes. Like most animals, humans are a diploid eukaryotic species. Each somatic cell has two sets of 23 chromosomes, each set received from one parent; gametes have only one set of chromosomes, which is a mixture of the two parental sets. Among the 23 pairs of chromosomes there are 22 pairs of autosomes and one pair of sex chromosomes.
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Research suggests that the frequency of mutations is generally higher in somatic cells than in cells of the germline; furthermore, there are differences in the types of mutation seen in the germ and in the soma. There is variation in mutation frequency between different somatic tissues within the same organism and between species. Milholland et al. (2017) examined the mutation rate of dermal fibroblasts (a type of somatic cell) and germline cells in humans and in mice.
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Sir Ian Wilmut, OBE FRS \--FMedSci FRSE (born 7 July 1944) is an English biologist, embryologist and Chair of the Scottish Centre for Regenerative Medicine at the University of Edinburgh. He is best known as the leader of the research group that in 1996 first cloned a mammal from an adult somatic cell, a Finnish Dorset lamb named Dolly. He was appointed OBE in 1999 for services to embryo development and knighted in the 2008 New Year Honours.
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Since his PhD, he has been involved in research focusing on gametes and embryogenesis, including working at the Roslin Institute. Wilmut was the leader of the research group that in 1996 first cloned a mammal, a lamb named Dolly. Dolly died of a respiratory disease in 2003. However, in 2008 Wilmut announced that he would abandon the technique of somatic cell nuclear transfer by which Dolly was created in favour of an alternative technique developed by Shinya Yamanaka.
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This type of cell fusion is widely used for the production of somatic cell hybrids and for nuclear transfer in mammalian cloning. Sendai virus induced cell fusion occurs in four different temperature stages. During the first stage, which lasts no longer than 10 minutes, viral adsorption takes place and the adsorbed virus can be inhibited by viral antibodies. The second stage, which is 20 minutes, is pH dependent and an addition of viral antiserum can still inhibit ultimate fusion.
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A dominant- negative mutation may arise in a human somatic cell and provide a proliferative advantage to the mutant cell, leading to its clonal expansion. For instance, a dominant-negative mutation in a gene necessary for the normal process of programmed cell death (Apoptosis) in response to DNA damage can make the cell resistant to apoptosis. This will allow proliferation of the clone even when excessive DNA damage is present. Such dominant-negative mutations occur in the tumor suppressor gene p53.
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It is at this junctional zone that several hundred fusion pores form, allowing for the mutual exchange of protein, RNA and eventually a meiotic product of their micronucleus. This whole process takes about 12 hours at 30 °C, but even longer than this at cooler temperatures. The sequence of events during conjugation is outlined in the accompanying figure. The larger polyploid macronucleus is transcriptionally active, meaning its genes are actively expressed, and so it controls somatic cell functions during vegetative growth.
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In 2000, after joining PPL Ltd, Campbell and his PPL team (based in North America) were successful in producing the world's first piglets by Somatic-cell nuclear transfer (SCNT), the so-called cloning technique. Furthermore, the PPL teams based in Roslin, Scotland and Blacksburg (USA) used the technique to produce the first gene targeted domestic animals as well as a range of animals producing human therapeutic proteins in their milk.Campbell, K. & Wilmut, I. (1998) "Nuclear Transfer". Animal Breeding: Technology for the 21st Century.
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Ced-3 is one of the major protein components of the programmed cell death (PCD) pathway for Caenorhabditis elegans. There are in total 14 genes that are involved in programmed cell death, other important ones including ced-4 and ced-9 genes. The healthy nematode worm will require 131 somatic cell deaths out of the 1090 cells during the developmental stages. The gene initially encodes for a prototypical caspase (procaspase) where the active cysteine residue cleaves aspartate residues, thus becoming a functional caspase.
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It was first seen on film in Star Wars: Episode II – Attack of the Clones (2002). There are major differences between the current ability to clone humans and those seen in Star Wars. Current human cloning methods need to use the somatic cell nuclear transfer (SCNT), which requires an unfertilized egg from a female donor to its nucleus removed, resulting in an enucleated egg. DNA from the subject being cloned would need to be extracted and electronically fused together with the enucleated egg.
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Kruppel-like factor 4 (KLF4; gut-enriched Krüppel-like factor or GKLF) is a member of the KLF family of zinc finger transcription factors, which belongs to the relatively large family of SP1-like transcription factors. KLF4 is involved in the regulation of proliferation, differentiation, apoptosis and somatic cell reprogramming. Evidence also suggests that KLF4 is a tumor suppressor in certain cancers, including colorectal cancer. It has three C2H2-zinc fingers at its carboxyl terminus that are closely related to another KLF, KLF2.
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In this case, one or more specific tissues are targeted by direct treatment or by removal of the tissue, addition of the therapeutic gene or genes in the laboratory, and return of the treated cells to the patient. Clinical trials of somatic cell gene therapy began in the late 1990s, mostly for the treatment of cancers and blood, liver, and lung disorders. Despite a great deal of publicity and promises, the history of human gene therapy has been characterized by relatively limited success.
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Present treatments of Parkinson's disease provide satisfactory disease control for most early-stage patients. However, present gold-standard treatment of PD using levodopa is associated with motor complications, and does not prevent disease progression. More effective and long-term treatment of PD are urgently needed to control its progression. In vivo gene therapy is a new approach for treatment of PD. The use of somatic-cell gene transfer to alter gene expression in brain neurochemical systems is a novel alternative conventional treatment.
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The disease specific stem cell lines could then be studied in order to better understand the condition. Another application of SCNT stem cell research is using the patient specific stem cell lines to generate tissues or even organs for transplant into the specific patient. The resulting cells would be genetically identical to the somatic cell donor, thus avoiding any complications from immune system rejection. Only a handful of the labs in the world are currently using SCNT techniques in human stem cell research.
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There lies a problem in the human cell's ability to form a blastocyst; the cells fail to progress past the eight cell stage of development. This is thought to be a result from the somatic cell nucleus being unable to turn on embryonic genes crucial for proper development. These earlier experiments used procedures developed in non-primate animals with little success. A research group from the Oregon Health & Science University demonstrated SCNT procedures developed for primates successfully using skin cells.
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This proposed mechanism has been shown to possibly be more complex in that FRQ may regulate WC-1 and WC-2 independently. Recently the transcription factor ADV-1 was identified as a necessary transducer of clock outputs, including circadian rhythmicity in genes critical to somatic cell fusion. The frq gene is strongly induced by short duration exposure to light. Because the core of the clock is based on rhythmic expression of frq, acute light-induction provides a straightforward way to reset the clock.
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Nuclear sexing is a technique for genetic sex determination in those species where XX chromosome pair is present. Nuclear sexing can be done by identifying Barr body, a drumstick like appendage located in the rim of the nucleus in somatic cells. Barr body is the inactive X chromosome which lies condensed in the nucleus of somatic cells. A typical human (or other XY-based organism) female has only one Barr body per somatic cell, while a typical human male has none.
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On the other hand, a mutation may occur in a somatic cell of an organism. Such mutations will be present in all descendants of this cell within the same organism. The accumulation of certain mutations over generations of somatic cells is part of cause of malignant transformation, from normal cell to cancer cell. Cells with heterozygous loss-of-function mutations (one good copy of gene and one mutated copy) may function normally with the unmutated copy until the good copy has been spontaneously somatically mutated.
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In 2001, McHugh was appointed by President George W. Bush to the Presidential Council on Bioethics. The Council was charged with the task of making recommendations as to what the U.S. federal government's policy regarding embryonic stem cells should be. McHugh was against using new lines of embryonic stem cells derived from in vitro fertilization but was in favor of the use of stem cells derived from somatic cell nuclear transfer (SCNT). In SCNT, the nucleus of a cell is removed and replaced by another cell nucleus.
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For instance, multilineage-differentiating stress-enduring (Muse) cells are stress-tolerant adult human stem cells that can self-renew. They form characteristic cell clusters in suspension culture that express a set of genes associated with pluripotency and can differentiate into endodermal, ectodermal and mesodermal cells both in vitro and in vivo. Other well-documented examples of transdifferentiation and their significance in development and regeneration were described in detail. Induced totipotent cells usually can be obtained by reprogramming somatic cells by somatic-cell nuclear transfer (SCNT).
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Beutler immediately recognized that this might account for the variable expression of X-linked genes in females heterozygous for X-linked mutations. He soon determined that random X chromosome inactivation causes tissue mosaicism in female mammals, in that each somatic cell expresses one (but not both) of the alleles of X-linked genes with which it is endowed. This he accomplished by showing that two populations of erythrocytes exist in the blood of African American women who are heterozygous for G6PD deficiency.Beutler, E. et al.
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Corynebacterium bovis is a pathogenic bacterium that causes mastitis and pyelonephritis in cattle. C. bovis is a facultatively anaerobic, Gram-positive organism, characterized by nonencapsulated, nonsporulated, immobile, straight or curved rods with a length of 1 to 8 µm and width of 0.3 to 0.8 µm, which forms ramified aggregations in culture (looking like "Chinese characters"). In mastitic infections, C. bovis is spread from cow to cow most commonly through improper milking technique. However, it is usually a mild infection resulting in an elevated somatic cell count.
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Loss of telomeric DNA through repeated cycles of cell division is associated with senescence or somatic cell aging. In contrast, germ line and cancer cells possess an enzyme, telomerase, which prevents telomere degradation and maintains telomere integrity, causing these types of cells to be very long-lived. In humans, the role of subtelomere disorders is demonstrated in facioscapulohumeral muscular dystrophy (FSHD), Alzheimer's disease, and peculiar syndromic diseases (malformation and mental retardation). For example, FSHD is associated with a deletion in the subtelomeric region of chromosome 4q.
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There, she worked with molecular biologist David Hirsh who was studying the model organism Caenorhabditis elegans. Kimble then moved to the MRC Laboratory of Molecular Biology, where she spent four years as a postdoctoral fellow working with Sir John Sulston on the control of organogenesis. During the course of her work, Kimble found a special somatic cell at the tip of the gonad which tells nearby germ cells - reproductive cells - how to divide. When she destroyed the distal tip cell, germ cells stopped dividing.
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The DNA of a cell is vulnerable to the damaging effect of oxidative free radicals produced as byproducts of cellular metabolism. DNA damage occurring in oocytes, if not repaired, can be lethal and result in reduced fecundity and loss of potential progeny. Oocytes are substantially larger than the average somatic cell, and thus considerable metabolic activity is necessary for their provisioning. If this metabolic activity were carried out by the oocyte’s own metabolic machinery, the oocyte genome would be exposed to the reactive oxidative by- products generated.
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The axons of lamprey are particularly large and allow for microinjection of substances for experimental manipulation. They are also capable of full functional recovery after complete spinal cord transection. Another trait is the ability to delete several genes from their somatic cell lineages, about 20% of their DNA, which are vital during development of the embryo, but which in humans can cause problems such as cancer later in life, after they have served their purpose. How the genes destined for deletion are targeted is not yet known.
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The production of Dolly showed that genes in the nucleus of such a mature differentiated somatic cell are still capable of reverting to an embryonic totipotent state, creating a cell that can then go on to develop into any part of an animal. Dolly's existence was announced to the public on 22 February 1997. It gained much attention in the media. A commercial with Scottish scientists playing with sheep was aired on TV, and a special report in Time magazine featured Dolly the sheep.
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There remained the question of whether the same success could be accomplished using adult somatic cells. Epigenetic and age related changes were thought to possibly hinder an adult somatic cells ability to be reprogrammed. Implementing the procedure pioneered by the Oregon research group they indeed were able to grow stem cells generated by SCNT using adult cells from two donors aged 35 and 75, indicating that age does not impede a cell's ability to be reprogrammed.Human Somatic Cell Nuclear Transfer Using Adult Cells Cell Stem Cell.
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William Morris visited in March 1887, noting in his Socialist Diary that Roslin was "a beautiful glen-ny landscape much spoiled . . . by the misery of Scotch building and a manufactory or two." On the north-western side of the village used to be Roslin Institute, a biological research establishment, where in 1996 Dolly the sheep became the first animal to be cloned from an adult somatic cell.1997: Dolly the sheep is cloned On This Day, BBC News online It moved to Easter Bush in 2011.
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Linder, D & Gartler, SM. 1965 Glucose-6-phosphate dehydrogenase mosaicism: utilization as a cell marker in the study of leiomyomas. Science 150:67-69Linder D & Gartler, SM. 1965 Problem of single cell versus multicell origin of a tumor. Proc 5th Berkeley Symp Math Stat & Prob 625-633 The clonal origin of tumors has been confirmed many times since, initially through the work of a junior colleague Philip J. Fialkow. In 1967, Gartler was interested in establishing a system for studying human genetics in somatic cell culture.
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This method includes the irradiation of cells to disrupt the genome into the desired number of fragments that are subsequently fused with Chinese hamster cells. The resulting somatic cell hybrids contain individual fragments of the relevant genome. Then, 90–100 (sometimes, more) clones covering the total genome are selected, and the sequences of interest are localized on the cloned fragments via the polymerase chain reaction (PCR) or direct DNA–DNA hybridization. To compare the genomes and chromosomes of two species, RHs should be obtained for both species.
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There was a slight delay between the original nucleus population and the rest of the commercial population of around 5–7 years. Today, the program has expanded its focus to improving other important aspects such as udder quality, lower somatic cell counts, and milk components. Since the program began, there has been an improvement of over 5 L per lactation, 0.19 g/L of fat content, and 0.17 g/L of crude protein content. The Lacaune breed, due to this extensive program, has the most studied genetics than any dairy sheep breed in the world.
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Mu-ming Poo (; born October 31, 1948) is a Chinese-American neuroscientist. He is the Paul Licht Distinguished Professor Emeritus at the University of California, Berkeley and the Founding Director of the Shanghai-based Institute of Neuroscience (ION) of the Chinese Academy of Sciences. He was awarded the 2016 Gruber Prize in Neuroscience for his pioneering work on synaptic plasticity. At ION, Poo led a team of scientists that produced the world's first truly cloned primates, a pair of crab-eating macaques called Zhongzhong and Huahua in 2017, using somatic cell nuclear transfer (SCNT).
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Eventually, either fatal damage is done to the cell's chromosomes (killing it via apoptosis), or an additional mutation that activates telomerase occurs. With telomerase activation some types of cells and their offspring become immortal (bypass the Hayflick limit), thus avoiding cell death as long as the conditions for their duplication are met. Many cancer cells are considered 'immortal' because telomerase activity allows them to live much longer than any other somatic cell, which, combined with uncontrollable cell proliferationDr. Todd Hennessey, 2016 University at Buffalo is why they can form tumors.
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In somatic cell nuclei, however, actin filaments cannot be observed using this technique. The DNase I inhibition assay, so far the only test which allows the quantification of the polymerized actin directly in biological samples, has revealed that endogenous nuclear actin indeed occurs mainly in a monomeric form. Precisely controlled level of actin in the cell nucleus, lower than in the cytoplasm, prevents the formation of filaments. The polymerization is also reduced by the limited access to actin monomers, which are bound in complexes with ABPs, mainly cofilin.
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Short communication: Fertility, somatic cell score, and production of Normande x Holstein, Montbéliarde x Holstein, and Scandinavian Red x Holstein crossbreeds versus pure Holsteins during their first 5 lactations Abbreviated Summary: Scandinavian Red x Holstein crossbred animals had fewer days to first breeding, enhanced first-service conception rates, higher pregnancy rates, and 12 to 26 fewer days open than did pure Holstein cows during their first 5 lactations. Therefore, the Scandinavian Red is a candidate breed for crossbreeding with Holstein to improve fertility and udder health of herds with higher mean production.
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In somatic cell gene therapy (SCGT), the therapeutic genes are transferred into any cell other than a gamete, germ cell, gametocyte, or undifferentiated stem cell. Any such modifications affect the individual patient only, and are not inherited by offspring. Somatic gene therapy represents mainstream basic and clinical research, in which therapeutic DNA (either integrated in the genome or as an external episome or plasmid) is used to treat disease. Over 600 clinical trials utilizing SCGT are underway in the US. Most focus on severe genetic disorders, including immunodeficiencies, haemophilia, thalassaemia, and cystic fibrosis.
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With Robert William Briggs, he worked on transplantation of somatic cell nuclei from adult frogs into enucleated oocytes this leading to the first clone of an animal in 1952. He was a scientist at the Institute for Cancer Research of the Lankenau Hospital Research Institute (now known as Lankenau Institute for Medical Research) when the work was conducted. King and Briggs were awarded in 1972 the highest honor of the French Academy: the Grand Prix Charles-Leopold Mayer of the Académie des Sciences, Institut de France and were the first Americans to be so honored.
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Mass culture of animal cell lines is fundamental to the manufacture of viral vaccines and other products of biotechnology. Culture of human stem cells is used to expand the number of cells and differentiate the cells into various somatic cell types for transplantation. Stem cell culture is also used to harvest the molecules and exosomes that the stem cells release for the purposes of therapeutic development. Biological products produced by recombinant DNA (rDNA) technology in animal cell cultures include enzymes, synthetic hormones, immunobiologicals (monoclonal antibodies, interleukins, lymphokines), and anticancer agents.
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Mammalian PGCs are specified by signalling between cells (induction), rather than by the segregation of germ plasm as the embryo divides. In mice, PGCs originate from the proximal epiblast, close to the extra-embryonic ectoderm (ExE), of the post-implantation embryo as early as embryonic day 6.5. By E7.5 a founding population of approximately 40 PGCs are generated in this region of the epiblast in the developing mouse embryo. The epiblast, however, also give rise to somatic cell lineages that make up the embryo proper; including the endoderm, ectoderm and mesoderm.
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Somatic recombination, as opposed to the genetic recombination that occurs in meiosis, is an alteration of the DNA of a somatic cell that is inherited by its daughter cells. The term is usually reserved for large-scale alterations of DNA such as chromosomal translocations and deletions and not applied to point mutations. Somatic recombination occurs physiologically in the assembly of the B cell receptor and T-cell receptor genes (V(D)J recombination), as well as in the class switching of immunoglobulins. Somatic recombination is also important in the process of carcinogenesis.
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Four-well plastic paddle The California mastitis test (CMT) is a simple cow- side indicator of the somatic cell count of milk. It operates by disrupting the cell membrane of any cells present in the milk sample, allowing the DNA in those cells to react with the test reagent, forming a gel.David White, Michael Walmsley, Alvin Liew, Rod Claycomb and Graeme Mein (2005): "Chemical and rheological aspects of gel formation in the California Mastitis Test", Journal of Dairy Research, 72:115-121 It provides a useful technique for detecting subclinical cases of mastitis.
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To date, the ideal progenitor cells have not been found or created. With the goal of recreating human tissue, the use of embryonic stem cells (ESC) was the initial logical choice. These pluripotent cells can conceptually give rise to any somatic cell line in the human body and while animal studies have shown restoration of cardiac function, immunologic rejection issues and teratoma formation have rendered ESC's a high risk. Human-induced pluripotent stem cells (iPSCs) are a cell line derived from somatic cells which have been induced through a combination of transcription factors.
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The Gene Regulation, Stem Cells, and Cancer program focus on mechanisms of gene expression, mechanisms of epigenetic regulation, and the molecular underpinnings of cellular operations pertaining to tissue homeostasis and cancer. Gene regulation studies include the organization and evolution of the regulatory genome, chromatin composition and transcriptional regulation mediated by steroid hormones, epigenetic mechanisms in leukemia and stem cells, regulation of periodic splicing and mRNA translation, and gene function and epigenetic reprogramming in embryogenesis and the germline. Stem cell research includes differentiation and transdifferentiation in the hematopoietic system, somatic cell reprogramming, and tissue regeneration.
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Protamines substitute for histones in the chromatin of sperm during the haploid phase of spermatogenesis, and are the major DNA-binding proteins in the nucleus of sperm in many vertebrates. They package the sperm DNA into a highly condensed complex in a volume less than 5% of a somatic cell nucleus. Many mammalian species have only one protamine (protamine 1); however, a few species, including human and mouse, have two. This gene encodes protamine 2, which is cleaved to give rise to a family of protamine 2 peptides.
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In plants, genetic changes in somatic lines can and do result in genetic changes in the germ lines, because the germ cells are produced by somatic cell lineages (vegetative meristems), which may be old enough (many years) to have accumulated multiple mutations since seed germination, some of them subject to natural selection. Likewise, basal animals such as sponges (Porifera) and corals (Anthozoa) contain multipotent stem cell lineages, that give rise to both somatic and reproductive cells. The Weismann barrier appears to be of a more recent evolutionary origin.
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Model of an adult, Naturkundemuseum Stuttgart The existence of frozen soft tissue remains and DNA of woolly mammoths has led to the idea that the species could be revived by scientific means. Several methods have been proposed to achieve this. Cloning would involve removal of the DNA-containing nucleus of the egg cell of a female elephant, and replacement with a nucleus from woolly mammoth tissue, a process called somatic cell nuclear transfer. For example, Akira Iritani, at the Kyoto University in Japan, reportedly planned to do this.
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Gene therapy involves supplying a functional gene to cells lacking that function, with the aim of correcting a genetic disorder or acquired disease. Gene therapy can be broadly divided into two categories. The first is alteration of germ cells, that is, sperm or eggs, which results in a permanent genetic change for the whole organism and subsequent generations. This “germ line gene therapy” is considered by many to be unethical in human beings. The second type of gene therapy, “somatic cell gene therapy”, is analogous to an organ transplant.
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After being inserted into the egg, the somatic cell nucleus is reprogrammed by its host egg cell. The ovum, now containing the somatic cell's nucleus, is stimulated with a shock and will begin to divide. The egg is now viable and capable of producing an adult organism containing all the necessary genetic information from just one parent. Development will ensue normally and after many mitotic divisions, this single cell forms a blastocyst (an early stage embryo with about 100 cells) with an identical genome to the original organism (i.e.
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Histone methylation occurs on arginine, lysine and histidine amino acids residues. Mono-, di- or tri-methylation has been discovered on histone H2A, H3 and H4. Histone methylation has been associated with various cellular functions such as transcription, DNA replication, and DNA damage response including repair, heterochromatin formation, and somatic cell reprogramming. Among these biological functions, transcriptional repression and activation are the most studied. Studies have shown that H4R3 methylation by PRMT1 (a histone methyltransferase) appears to be essential in vivo for the establishment or maintenance of a wide range of “active” chromatin modifications.
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This gene encodes a protein belonging to the glyceraldehyde-3-phosphate dehydrogenase family of enzymes that play an important role in carbohydrate metabolism. Like its somatic cell counterpart, this sperm-specific enzyme functions in a nicotinamide adenine dinucleotide-dependent manner to remove hydrogen and add phosphate to glyceraldehyde 3-phosphate to form 1,3-diphosphoglycerate. During spermiogenesis, this enzyme may play an important role in regulating the switch between different energy-producing pathways, and it is required for sperm motility and male fertility. In melanocytic cells GAPDHS gene expression may be regulated by MITF.
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A 10 - 20 μm large somatic cell generally needs 24 hours to double its mass for mitosis. By this way it would take a very long time for that cell to reach the size of a mammalian egg with a diameter of 100 μm (some insects have eggs of about 1,000 μm or greater). Eggs have therefore special mechanisms to grow to their large size. One of these mechanisms is to have extra copies of genes: meiotic division I is paused so that the oocyte grows while it contains two diploid chromosome sets.
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ART techniques are also used to improve the profitability of agricultural animal species such as cows and pigs by enabling selective breeding for desired traits and/or to increase numbers of offspring. For example, when allowed to breed naturally, cows typically produce one calf per year, whereas IVF increases offspring yield to 9-12 calves per year. IVF and other ART techniques, including cloning via interspecies somatic cell nuclear transfer (iSCNT), are also used in attempts to increase the numbers of endangered or vulnerable species, such as Northern white rhinos, cheetahs, and sturgeons.
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Cancer occurs when a somatic cell which normally cannot divide undergoes mutations which cause de-regulation of the normal cell cycle controls leading to uncontrolled proliferation. Immortalised cell lines have undergone similar mutations allowing a cell type which would normally not be able to divide to be proliferated in vitro. The origins of some immortal cell lines, for example HeLa human cells, are from naturally occurring cancers. HeLa, the first-ever immortal human cell line, was taken from Henrietta Lacks (without informed consent) in 1951 at Johns Hopkins Hospital in Baltimore, Maryland.
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Human iPS cells colonies. The spindle-shaped cells in the background are mouse fibroblast cells. Only those cells comprising the center colony are human iPS cells. Induced pluripotent stem cells (also known as iPS cells or iPSCs) are a type of pluripotent stem cell that can be generated directly from a somatic cell. The iPSC technology was pioneered by Shinya Yamanaka’s lab in Kyoto, Japan, who showed in 2006 that the introduction of four specific genes (named Myc, Oct3/4, Sox2 and Klf4) encoding transcription factors could convert somatic cells into pluripotent stem cells.
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Somatic cells of different types can be fused to obtain hybrid cells. Hybrid cells are useful in a variety of ways, e.g., (i) to study the control of cell division and gene expression, (ii) to investigate malignant transformations, (iii) to obtain viral replication, (iv) for gene or chromosome mapping and for (v) production of monoclonal antibodies by producing hybridoma (hybrid cells between an immortalised cell and an antibody producing lymphocyte), etc. Chromosome mapping through somatic cell hybridization is essentially based on fusion of human and mouse somatic cells.
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In 1952, Robert Briggs and Thomas J. King cloned a frog by somatic cell nuclear transfer. This same technique was later used to create Dolly the sheep, and their experiment was the first time a successful nuclear transplantation had been accomplished in higher animals. Frogs are used in cloning research and other branches of embryology. Although alternative pregnancy tests have been developed, biologists continue to use Xenopus as a model organism in developmental biology because their embryos are large and easy to manipulate, they are readily obtainable, and can easily be kept in the laboratory.
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The Institute of Electrical and Electronics Engineers (IEEE) has placed the name of Surena among the five prominent robots of the world after analyzing its performance. In the biomedical sciences, Iran's Institute of Biochemistry and Biophysics has a UNESCO chair in biology. In late 2006, Iranian scientists successfully cloned a sheep by somatic cell nuclear transfer, at the Royan Research Center in Tehran. According to a study by David Morrison and Ali Khadem Hosseini (Harvard-MIT and Cambridge), stem cell research in Iran is amongst the top 10 in the world.
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It took another fifteen to twenty years, using somatic cell genetics, to show that the interferon action gene and interferon gene reside in different human chromosomes. The purification of human beta interferon did not occur until 1977. Y.H. Tan and his co-workers purified and produced biologically active, radio-labeled human beta interferon by superinducing the interferon gene in fibroblast cells, and they showed its active site contains tyrosine residues. Tan's laboratory isolated sufficient amounts of human beta interferon to perform the first amino acid, sugar composition and N-terminal analyses.
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Imprinting may cause problems in cloning, with clones having DNA that is not methylated in the correct positions. It is possible that this is due to a lack of time for reprogramming to be completely achieved. When a nucleus is added to an egg during somatic cell nuclear transfer, the egg starts dividing in minutes, as compared to the days or months it takes for reprogramming during embryonic development. If time is the responsible factor, it may be possible to delay cell division in clones, giving time for proper reprogramming to occur.
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Since scientists produced the first cloned mammal Dolly the sheep in 1996 using the somatic cell nuclear transfer (SCNT) technique, 23 mammalian species have been successfully cloned, including cattle, cats, dogs, horses and rats. Using this technique for primates had never been successful and no pregnancy had lasted more than 80 days. The main difficulty was likely the proper programming of the transferred nuclei to support the growth of the embryo. Tetra (born October 1999), a female rhesus macaque, was created by a team led by Gerald Schatten of the Oregon National Primate Research Center using a different technique, called "embryo splitting".
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An example of this is the modern cultivated species of wheat, Triticum aestivum L., a hexaploid species whose somatic cells contain six copies of every chromatid. The frequency of spontaneous mutations is significantly lower in advanced male germ cells than in somatic cell types from the same individual. Female germ cells also show a mutation frequency that is lower than that in corresponding somatic cells and similar to that in male germ cells. These findings appear to reflect employment of more effective mechanisms to limit the initial occurrence of spontaneous mutations in germ cells than in somatic cells.
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The claims of his research results resulted in him receiving the Scientist of the Year Award by the Korea Science Journalists Association. Until 2004, Hwang's main area of research remained in creating genetically modified livestock that included cows and pigs. During that period, Hwang claimed to have created a BSE-resistant cow (which has not been verified) and also stated his intention to clone a Siberian tiger. In February 2004, Hwang and his team announced that they had successfully created an embryonic stem cell with the somatic cell nuclear transfer method, and published their paper in the March 12 issue of Science.
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With John Watkins he developed the technique of cell fusion for the study of the physiology and genetics of higher cells. They demonstrated that cell fusion provided a general method for the amalgamation of different cell types across the barriers imposed by species differences and by the process of differentiation.Hybrid Cells Derived from Mouse and Man : Artificial Heterokaryons of Mammalian Cells from Different Species HENRY HARRIS & J. F. WATKINS Nature 205, 640 - 646 (1965). This technique was one of the main roots of somatic cell genetics and, in due course, resulted in the production of monoclonal antibodies.
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Users can design a rAAV vector to any target genomic locus and perform both gross and subtle endogenous gene alterations in mammalian somatic cell-types. These include gene knock-outs for functional genomics, or the ‘knock-in’ of protein tag insertions to track translocation events at physiological levels in live cells. Most importantly, rAAV targets a single allele at a time and does not result in any off-target genomic alterations. Because of this, it is able to routinely and accurately model genetic diseases caused by subtle SNPs or point mutations that are increasingly the targets of novel drug discovery programs.
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In this approach, transcription factors from progenitor cells of the target cell type are transfected into a somatic cell to induce transdifferentiation. There exists two different means of determining which transcription factors to use: by starting with a large pool and narrowing down factors one by one or by starting with one or two and adding more. One theory to explain the exact specifics is that ectopic Transcriptional factors direct the cell to an earlier progenitor state and then redirects it towards a new cell type. Rearrangement of the chromatin structure via DNA methylation or histone modification may play a role as well.
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In 1995, two ewes named Megan and Morag were the first mammals cloned from differentiated cells. A year later, a Finnish Dorset sheep named Dolly, dubbed "the world's most famous sheep" in Scientific American, was the first mammal to be cloned from an adult somatic cell. Following this, Polly and Molly were the first mammals to be simultaneously cloned and transgenic. As of 2008, the sheep genome has not been fully sequenced, although a detailed genetic map has been published, and a draft version of the complete genome produced by assembling sheep DNA sequences using information given by the genomes of other mammals.
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Christopher Reeve Testimony: March 5, 2002. Accessed November 30, 2006 In June 2004, Reeve provided a videotaped message on behalf of the Genetics Policy Institute to the delegates of the United Nations in defense of somatic cell nuclear transfer, which a world treaty was considering banning. In the final days of his life, Reeve urged California voters to vote yes on Proposition 71,Reeve stem cell appeal airs in US. BBC News, October 23, 2004. Accessed November 30, 2006 which would establish the California Institute for Regenerative Medicine and would allot $3 billion of state funds to stem cell research.
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2010 Bodmer developed models for population genetics and worked on the human leukocyte antigen system and the use of somatic cell hybrids for human linkage studies. In 1985 he chaired a Royal Society committee which wrote The Bodmer Report; this has been credited with starting the movement for the public understanding of science. Bodmer was one of the first to suggest the idea of the Human Genome Project. In 1987 he received the Ellison-Cliffe Medal from the Royal Society of Medicine. He was the director of research (1979–1991) and then Director General (1991–1996) of the Imperial Cancer Research Fund.
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It is not clear if the embryos produced would have been capable of further development, but Dr. Wood stated that if that were possible, using the technology for reproductive cloning would be both unethical and illegal. The 5 cloned embryos, created in Stemagen Corporation lab, in La Jolla, were later destroyed to confirm the nuclear transfer process.Weiss, Rick Mature Human Embryos Created From Adult Skin Cells Washingtonpost.com Dr. French, lead author, and five other researchers published their findings in the online research journal Stem Cells, in an article entitled Development of human cloned blastocysts following somatic cell nuclear transfer (SCNT) with adult fibroblasts.
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Human germline engineering is a process in which the human genome is edited within a germ cell, such as a sperm cell or oocyte (causing heritable changes), or in the zygote or embryo following fertilisation. Germline engineering results in changes in the genome being incorporated into every cell in the body of the offspring (or of the individual following embryonic germline engineering). This process differs from somatic cell engineering, which does not result in heritable changes. Most human germline editing is performed on individual cells and non-viable embryos, which are destroyed at a very early stage of development.
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Dolly was born on 5 July 1996 and had three mothers: one provided the egg, another the DNA, and a third carried the cloned embryo to term. She was created using the technique of somatic cell nuclear transfer, where the cell nucleus from an adult cell is transferred into an unfertilized oocyte (developing egg cell) has had its cell nucleus removed. The hybrid cell is then stimulated to divide by an electric shock, and when it develops into a blastocyst it is implanted in a surrogate mother. Dolly was the first clone produced from a cell taken from an adult mammal.
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The gene is a unit of hereditary information that exists in many physical copies in the world, and which particular physical copy will be replicated and originate new copies does not matter from the gene's point of view. A selfish gene could be favored by selection by producing altruism among organisms containing it. The idea is summarized as follows: A gene in a somatic cell of an individual may forego replication to promote the transmission of its copies in the germ line cells. It ensures the high value of p = 1 due to their constant contact and their common origin from the zygote.
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Interspecies nuclear transfer (iSCNT) is a means of somatic cell nuclear transfer used to facilitate the rescue of endangered species, or even to restore species after their extinction. The technique is similar to SCNT cloning which typically is between domestic animals and rodents, or where there is a ready supply of oocytes and surrogate animals. However, the cloning of highly endangered or extinct species requires the use of an alternative method of cloning. Interspecies nuclear transfer utilizes a host and a donor of two different organisms that are closely related species and within the same genus.
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Relationship between fully differentiated "old" cells, pluripotent stem cells produced through classical cloning, and "young" cells produced by partial cloning. In the field of cell biology, the method of partial cloning (PCL) converts a fully differentiated old somatic cell into a partially reprogrammed young cell that retains all the specialised functions of the differentiated old cell but is simply younger. The method of PCL reverses characteristics associated with old cells. For example, old, senescent, cells rejuvenated by PCL are free of highly condensed senescence-associated heterochromatin foci (SAHF) and re-acquire the proliferation potential of young cells.
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If a mutation occur in a somatic cell of an organism, it will be present in all descendants of this cell within the same organism. The accumulation of certain mutations over generations of somatic cells is part of the process of malignant transformation, from normal cell to cancer cell. Cells with heterozygous loss-of-function mutations (one good copy of a gene and one mutated copy) may function normally with the unmutated copy until the good copy has been spontaneously somatically mutated. This kind of mutation happens often in living organisms, but it is difficult to measure the rate.
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A number of different cellular processes must take place in order for somatic cells to undergo reprogramming into induced pluripotent stem cells (iPS cells). iPS cell reprogramming, also known as somatic cell reprogramming, can be achieved by ectopic expression of Oct4, Klf4, Sox2, and c-Myc (OKSM). Upon induction, mouse fibroblasts must undergo MET to successfully begin the initiation phase of reprogramming. Epithelial- associated genes such as E-cadherin/Cdh1, Cldns −3, −4, −7, −11, Occludin (Ocln), Epithelial cell adhesion molecule (Epcam), and Crumbs homolog 3 (Crb3), were all upregulated before Nanog, a key transcription factor in maintaining pluripotency, was turned on.
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The somatic fusion process occurs in four steps: . # The removal of the cell wall of one cell of each type of plant using cellulase enzyme to produce a somatic cell called a protoplast # The cells are then fused using electric shock (electrofusion) or chemical treatment to join the cells and fuse together the nuclei. The resulting fused nucleus is called heterokaryon. # The formation of the cell wall is then induced using hormones # The cells are then grown into calluses which then are further grown to plantlets and finally to a full plant, known as a somatic hybrid.
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XCI is initiated very early during female embryonic development or upon differentiation of female embryonic stem (ES) cells and results in inactivation of one X chromosome in every female somatic cell. This process is initiated very early during development, around the two- to eight-cell stage and is maintained in the developing extra-embryonic tissues of the embryo, including the fetal placenta. Xist RNA induces heterochromatinization of the X chromosome by attracting chromatin modifiers, involved in gene silencing. Xist RNA is tightly associated with the Xi and it is required for X Chromosome Inactivation to occur in cis.
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Their laboratories worked together for 15 years, on multiple technologies for gene hunting, including radiation hybrid mapping, a method that uses high-energy x-rays to fragment human chromosomes that were recovered in somatic cell hybrids and then used to determine the locations of DNA markers in the human genome. In 1990 they established a human genome center, which they moved to Stanford University in early 1993. The pair continued working on inherited human diseases. They found the genes for an inherited form of childhood progressive epilepsy (EPM1), a gene important for a key step in development of the cerebellum (the “weaver” gene), and others.
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Induced totipotent cells can be obtained by reprogramming somatic cells with somatic-cell nuclear transfer (SCNT). The process involves sucking out the nucleus of a somatic (body) cell and injecting it into an oocyte that has had its nucleus removed Using an approach based on the protocol outlined by Tachibana et al., hESCs can be generated by SCNT using dermal fibroblasts nuclei from both a middle-aged 35-year-old male and an elderly, 75-year-old male, suggesting that age- associated changes are not necessarily an impediment to SCNT-based nuclear reprogramming of human cells. Such reprogramming of somatic cells to a pluripotent state holds huge potentials for regenerative medicine.
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Although Hwang had already established himself as an expert in animal cloning and secured celebrity status in South Korea in the late 90s, his alleged sudden success came as a surprise because this was the first reported success in human somatic cell cloning. Until Hwang's claim, it was generally agreed that creating a human stem cell by cloning was next to impossible due to the complexity of primates. Hwang explained that his team used 242 eggs to create a single cell line. In May, Nature magazine published an article stating that Hwang had used eggs taken from two of his graduate students, based on an interview with one of the students.
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Only three of these embryos survived until birth, and only one survived to adulthood. As the procedure could not be automated, and had to be performed manually under a microscope, SCNT was very resource intensive. The biochemistry involved in reprogramming the differentiated somatic cell nucleus and activating the recipient egg was also far from being well understood. However, by 2014 researchers were reporting cloning success rates of seven to eight out of tenShukman, David (14 January 2014) China cloning on an 'industrial scale' BBC News Science and Environment, Retrieved 10 April 2014 and in 2016, a Korean Company Sooam Biotech was reported to be producing 500 cloned embryos per day.
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Low-resolution physical mapping is typically capable of resolving DNA ranging from one base pair to several mega bases. In this category, most mapping methods involve generating a somatic cell hybrid panel, which is able to map any human DNA sequences, the gene of interest, to specific chromosomes of animal cells, such as those of mice and hamsters. The hybrid cell panel is produced by collecting hybrid cell lines containing human chromosomes, identified by polymerase chain reaction (PCR) screening with primers specific to the human sequence of interest as the hybridization probe. The human chromosome would be presented in all of the cell lines.
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The IBHF analyzes scientific research related to germline intervention and its implications to law and bioethics. Gene Patents Patents for human genetic material grant exclusivity over naturally occurring sequences of human genes and their effect on research and diagnosis. The IBHF reviews and analyzes the effects of gene patents on research, healthcare, business, and individual rights. Nanotechnology The IBHF reviews the development of nanotechnology policy in the United States and Europe, with special focus on the emerging nanotechnology ethical, legal, and social issues (NELSI). Human Cloning “Somatic cell nuclear transfer” technology can be used to bring about the birth of replica offspring, and to create embryos for experimentation.
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Somatic cells stained with Newman-Lampert Lewovitz-Weber solution (ISO 13366-1/2008) Somatic cells stained with ethidium bromide (ISO 13366-1/1997) Polymorfonuclear leukocyte stained with ethidium bromide (ISO 13366-1/2008) A somatic cell count (SCC) is a cell count of somatic cells in a fluid specimen, usually milk. In dairying, the SCC is an indicator of the quality of milk—specifically, its low likeliness to contain harmful bacteria, and thus its high food safety. White blood cells (leukocytes) constitute the majority of somatic cells in question. The number of somatic cells increases in response to pathogenic bacteria like Staphylococcus aureus, a cause of mastitis.
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Noori was born on 9 March 2012 to three mothers (one provided the egg, another the DNA and a third carried the cloned embryo to term). She was created using the technique of somatic cell nuclear transfer, in which the cell nucleus from an adult cell is transferred into an unfertilised oocyte (developing egg cell) that has had its nucleus removed. The hybrid cell is then stimulated to divide by an electric shock, and when it develops into a blastocyst, it is implanted in a surrogate mother using laparoscopic surgery. This is the same method as was used in cloning the first mammal of the world, Dolly.
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Embryos may be created by in vitro fertilization (IVF) with gametes from a male and female of the species to be reproduced. They may also be created by somatic cell nuclear transfer (SCNT) into an egg cell of another species, creating a cloned embryo that transferred into the uterus of yet another species. This technique was used for the experiment of panda fetuses in a cat mentioned in techniques for evercoming rejection. In this experiment, nuclei from cells taken from abdominal muscles of giant pandas were transferred to egg cells of rabbits and, in turn, transferred into the uterus of cat together with cat embryos.
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In In his Image, Rorvik claimed that in 1973 a wealthy businessman he dubbed "Max" had contacted him and recruited him to find scientists willing to create a clone of him. Rorvik claims to have formed a scientific team that was taken to a lab at a secret location. After a few years of experimentation they managed to implant a specially prepared body cell nucleus into the cytoplast of a human ovum (a technique known as somatic cell nuclear transfer) and, in turn, succeeded in implanting this egg into the uterus of a surrogate mother, a local resident called "Sparrow." A healthy child, it was claimed, was born nine months later.
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Someone with two X chromosomes (such as most human females) has only one Barr body per somatic cell, while someone with one X chromosome (such as most human males) has none. Mammalian X-chromosome inactivation is initiated from the X inactivation centre or Xic, usually found near the centromere. The center contains twelve genes, seven of which code for proteins, five for untranslated RNAs, of which only two are known to play an active role in the X inactivation process, Xist and Tsix. The centre also appears to be important in chromosome counting: ensuring that random inactivation only takes place when two or more X-chromosomes are present.
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The frequency of mutations in mouse somatic tissue (brain, liver, Sertoli cells) was compared to the mutation frequency in male germline cells at sequential stages of spermatogenesis. The spontaneous mutation frequency was found to be significantly higher (5 to 10-fold) in the somatic cell types than in the male germline cells. In female mice, somatic cells were also found to have a higher mutation frequency than germline cells. It was suggested that elevated levels of DNA repair enzymes play a prominent role in the lower mutation frequency of male and female germline cells, and that enhanced genetic integrity is a fundamental characteristic of germline cells.
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Although the methods pioneered by Yamanaka and others have demonstrated that adult cells can be reprogrammed to iPS cells, there are still challenges associated with this technology: # Low efficiency: in general, the conversion to iPS cells has been incredibly low. For example, the rate at which somatic cells were reprogrammed into iPS cells in Yamanaka's original mouse study was 0.01–0.1%. The low efficiency rate may reflect the need for precise timing, balance, and absolute levels of expression of the reprogramming genes. It may also suggest a need for rare genetic and/or epigenetic changes in the original somatic cell population or in the prolonged culture.
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Until the commercial development of mobile DNA technology in 2007 and zinc-finger nuclease technology in 2009, there were only two technologies that could be used to produce rat models of human disease: cloning and chemical mutagenesis using N-ethyl-N-nitrosourea (ENU). Although cloning by somatic cell nuclear transfer (SCNT) could theoretically be used to create rats with specific mutations by mutating somatic cells, and then using these cells for SCNT, this approach has not been used successfully to create knockout rats. One problem with this strategy is that SCNT is extremely inefficient. The first published attempt had a success rate of less than 1%.
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Ted Steele hypothesized the RNA/RT-based mechanism of somatic hypermutation. This is known as neo-Lamarckism.The implications of Steele's soma-to-germline feedback for the safety of somatic gene therapy in humans Steele's hypothesis provided the first mechanism to explain Lamarckian evolution: when successful somatic cell changes occur due to environmental changes, copies of the copious new messenger-RNA that have been produced by the successful cells are picked up by harmless retroviruses acting as gene shuttles and transported across the tissue barrier – the Weismann Barrier – to the germline. Finally, the new genetic information is integrated into the DNA by a process involving reverse transcription.
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However, iPSCs were found to be potentially tumorigenic, and, despite advances, were never approved for clinical stage research in the United States. Setbacks such as low replication rates and early senescence have also been encountered when making iPSCs, hindering their use as ESCs replacements. Additionally, it has been determined that the somatic expression of combined transcription factors can directly induce other defined somatic cell fates (transdifferentiation); researchers identified three neural-lineage-specific transcription factors that could directly convert mouse fibroblasts (skin cells) into fully functional neurons. This result challenges the terminal nature of cellular differentiation and the integrity of lineage commitment; and implies that with the proper tools, all cells are totipotent and may form all kinds of tissue.
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By using cells from a closely related species to the extinct species, genome editing can play a role in the de-extinction process. Germ cells may be edited directly, so that the egg and sperm produced by the extant parent species will produce offspring of the extinct species, or somatic cells may be edited and transferred via somatic cell nuclear transfer. This results in a hybrid between the two species, since it is not completely one animal. Because it is possible to sequence and assemble the genome of extinct organisms from highly degraded tissues, this technique enables scientists to pursue de-extinction in a wider array of species, including those for which no well-preserved remains exist.
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This compound and the ring structure on which it was based were patented, and both Newton and Abraham set up trusts out of the royalties that they received. The Edward Penley Abraham Research Fund, the EPA Cephalosporin Fund and the Guy Newton Research Fund are dedicated to the support of medical, biological and chemical research in the Dunn School, Lincoln College and the University of Oxford. Florey was succeeded as Professor in 1963 by Henry Harris, another expatriate Australian, who had arrived in Oxford in 1952 to do a DPhil under Florey’s supervision. Harris's main interest was in cell biology and especially what was later to become the science of somatic cell genetics.
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Some stem cell researchers are working to develop techniques of isolating stem cells that are as potent as embryonic stem cells, but do not require a human embryo. Foremost among these was the discovery in August 2006 that adult cells can be reprogrammed into a pluripotent state by the introduction of four specific transcription factors, resulting in induced pluripotent stem cells. This major breakthrough won a Nobel Prize for the discoverers, Shinya Yamanaka and John Gurdon. In an alternative technique, researchers at Harvard University, led by Kevin Eggan and Savitri Marajh, have transferred the nucleus of a somatic cell into an existing embryonic stem cell, thus creating a new stem cell line.
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The first person to successfully demonstrate reprogramming was John Gurdon, who in 1962 demonstrated that differentiated somatic cells could be reprogrammed back into an embryonic state when he managed to obtain swimming tadpoles following the transfer of differentiated intestinal epithelial cells into enucleated frog eggs. For this achievement he received the 2012 Nobel Prize in Medicine alongside Shinya Yamanaka. Yamanaka was the first to demonstrate (in 2006) that this somatic cell nuclear transfer or oocyte-based reprogramming process (see below), that Gurdon discovered, could be recapitulated (in mice) by defined factors (Oct4, Sox2, Klf4, and c-Myc) to generate induced pluripotent stem cells (iPSCs). Other combinations of genes have also been used.
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As the procedure was not automated, but had to be performed manually under a microscope, SCNT was very resource intensive. The biochemistry involved in reprogramming the differentiated somatic cell nucleus and activating the recipient egg was also far from understood. However, by 2014, researchers were reporting success rates of 70-80% with cloning pigsShukman, David (14 January 2014) China cloning on an 'industrial scale' BBC News Science and Environment, Retrieved 10 April 2014 and in 2016 a Korean company, Sooam Biotech, was reported to be producing 500 cloned embryos a day. In SCNT, not all of the donor cell's genetic information is transferred, as the donor cell's mitochondria that contain their own mitochondrial DNA are left behind.
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In the early 1970s, Russian theorist Alexei Olovnikov first recognized that chromosomes could not completely replicate their ends. Building on this, and to accommodate Leonard Hayflick's idea of limited somatic cell division, Olovnikov suggested that DNA sequences are lost every time a cell replicates until the loss reaches a critical level, at which point cell division ends. In 1975–1977, Elizabeth Blackburn, working as a postdoctoral fellow at Yale University with Joseph G. Gall, discovered the unusual nature of telomeres, with their simple repeated DNA sequences composing chromosome ends. Blackburn, Carol Greider, and Jack Szostak were awarded the 2009 Nobel Prize in Physiology or Medicine for the discovery of how chromosomes are protected by telomeres and the enzyme telomerase.
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The developmental fate of every single somatic cell (959 in the adult hermaphrodite; 1031 in the adult male) has been mapped. These patterns of cell lineage are largely invariant between individuals, whereas in mammals, cell development is more dependent on cellular cues from the embryo. As mentioned previously, the first cell divisions of early embryogenesis in C. elegans are among the best understood examples of asymmetric cell divisions, and the worm is a very popular model system for studying developmental biology. Programmed cell death (apoptosis) eliminates many additional cells (131 in the hermaphrodite, most of which would otherwise become neurons); this "apoptotic predictability" has contributed to the elucidation of some apoptotic genes.
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Embryonic stem cells capable of contributing to the germline of livestock species such as sheep have not been isolated. The production of Dolly the Sheep and also Megan and Morag, the two sheep that led to the production of Dolly, demonstrated that viable sheep can be produced by nuclear transfer from a variety of somatic cell types which have been cultured in vitro. Polly and Molly represented the further step in which somatic cells were cultured in vitro, just as in the case with the previous sheep. However, in this case they were transfected with foreign DNA, and the transfected cells which stably integrated this new piece of genetic information were selected.
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A somatic mutation is change in the DNA sequence of a somatic cell of a multicellular organism with dedicated reproductive cells; that is, any mutation that occurs in a cell other than a gamete, germ cell, or gametocyte. Unlike germline mutations, which can be passed on to the descendants of an organism, somatic mutations are not usually transmitted to descendants. This distinction is blurred in plants, which lack a dedicated germline, and in those animals that can reproduce asexually through mechanisms such as budding, as in members of the cnidarian genus Hydra. While somatic mutations are not passed down to an organism's offspring, somatic mutations will be present in all descendants of a cell within the same organism.
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Terminology surrounding biopharmaceuticals varies between groups and entities, with different terms referring to different subsets of therapeutics within the general biopharmaceutical category. Some regulatory agencies use the terms biological medicinal products or therapeutic biological product to refer specifically to engineered macromolecular products like protein- and nucleic acid-based drugs, distinguishing them from products like blood, blood components, or vaccines, which are usually extracted directly from a biological source. Specialty drugs, a recent classification of pharmaceuticals, are high-cost drugs that are often biologics. The European Medicines Agency uses the term advanced therapy medicinal products (ATMPs) for medicines for human use that are "based on genes, cells, or tissue engineering", including gene therapy medicines, somatic-cell therapy medicines, tissue-engineered medicines, and combinations thereof.
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Despite that callus exhibits a number of stem cell-like properties for a temporary period and that it has been cultured for useful plant compounds as an alternative source of plant stem cell, callus and plant stem cell are fundamentally different from each other. Callus is similar to plant stem cell in its ability to differentiate, but the two are different in their origin. While plant stem cell exists in the meristematic tissues of plant, callus is obtained as a temporary response to cure wounds in somatic cell. Moreover, callus undergoes dedifferentiation as differentiated cells acquire ability to differentiate; but genetic variation is inevitable in the process because the cells consist of somatic undifferentiated cells from an adult subject plant.
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Eggan's research goals at Harvard were to understand how nuclear transplantation works, and to make stem cells that carry genes for specific diseases such as Parkinson's disease, amyotrophic lateral sclerosis (Lou Gehrig's disease), and Alzheimer's. In 2006, following "more than two years of intensive ethical and scientific review", two groups of scientists at HSCI were granted permission to explore Somatic Cell Nuclear Transfer techniques to create disease-specific stem cell lines as an approach to various currently incurable conditions. Eggan was in charge of one of these two groups and senior author of their results; a renowned co-director of HSCI ran the other. The groups initially collaborated in researching diabetes before Eggan's group switched to work on neurodegenerative diseases.
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Researchers at Australian Regenerative Medicine Institute at Monash University, have published that when macrophages, which eat up material debris, were removed, salamanders lost their ability to regenerate and formed scarred tissue instead. In spite of the historically few researchers studying limb regeneration, remarkable progress has been made recently in establishing the neotenous amphibian the axolotl (Ambystoma mexicanum) as a model genetic organism. This progress has been facilitated by advances in genomics, bioinformatics, and somatic cell transgenesis in other fields, that have created the opportunity to investigate the mechanisms of important biological properties, such as limb regeneration, in the axolotl. The Ambystoma Genetic Stock Center (AGSC) is a self-sustaining, breeding colony of the axolotl supported by the National Science Foundation as a Living Stock Collection.
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Induced pluripotent stem cells, commonly abbreviated as iPS cells or iPSCs, are a type of pluripotent stem cell artificially derived from a non-pluripotent cell, typically an adult somatic cell, by inducing a "forced" expression of certain genes and transcription factors. These transcription factors play a key role in determining the state of these cells and also highlights the fact that these somatic cells do preserve the same genetic information as early embryonic cells. The ability to induce cells into a pluripotent state was initially pioneered in 2006 using mouse fibroblasts and four transcription factors, Oct4, Sox2, Klf4 and c-Myc; this technique, called reprogramming, earned Shinya Yamanaka and John Gurdon the Nobel Prize in Physiology or Medicine 2012."The Nobel Prize in Physiology or Medicine 2012". Nobelprize.org.
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Wrighton served as a presidential appointee to the National Science Board (2000-2006), which acts as science policy advisor to the President and Congress and the National Science Foundation. He served as vice chair of the National Research Council's Committee on America's Energy Future, which issued its report in 2009. While at Washington University in St. Louis, Wrighton was one of the signees of a letter from the Association of American Universities, urging all representatives of the U.S. Government to vote in favor of H.R. 810, the Stem Cell Research Enhancement Act of 2005. With leaders at three other Missouri universities, Wrighton wrote in support of somatic cell nuclear transfer (SCNT) research for medical treatment, urging Missouri legislators to distinguish it from the use of stem cells for human reproductive cloning.
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The super Carabao buffaloes at the milking and breeding station In 2007, the development of Southeast Asia's first cloned water buffalo was announced in the Philippines. The Department of Agriculture's Philippine Carabao Center implemented cloning through somatic cell nuclear transfer as a tool for genetic improvement in water buffaloes to produce "super buffalo calves" by multiplying existing germplasms, but without modifying or altering genetic material. In January 2008, the Philippine Carabao Center in Nueva Ecija, per Filipino scientists, initiated a study to breed a super water buffalo that could produce 4 to 18 litres of milk per day, using gene-based technology. Also, the first in vitro river buffalo was born there in 2004 from an in vitro-produced, vitrified embryo, named "Glory" after President Gloria Macapagal-Arroyo.
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And, while DNA binding transcription factors provide a mechanism for specific control of cellular responses, a model where DNA binding transcription factors are the sole regulators of gene activity is also unlikely. For example, in a study of Somatic-cell nuclear transfer, it was demonstrated that stable features of differentiation remain after the nucleus is transferred to a new cellular environment, suggesting that a stable and heritable mechanism of gene regulation was involved in the maintenance of the differentiated state in the absence of the DNA binding transcription factors. With the finding that DNA methylation and histone modifications are stable, heritable, and also reversible processes that influence gene expression without altering DNA primary structure, a mechanism for the observed variability in cell gene expression was provided. These modifications were termed epigenetic, from epi “on top of” the genetic material “DNA” (Epigenetics 1).
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Wood entered the arena of stem cell research shortly after the first published study of nuclear transfer stem cells (NTSC), also known as human therapeutic cloning, was withdrawn when the principal author's claims were called into question due to falsified data and ethical deviation from scientific research standards. Australian scientist, Andrew French, best known for his work with somatic cell nuclear transfer (SCNT) in the mammalian reproduction process, co-investigated with Wood and French's Australian colleague, Alan Trounson. Based on meticulous mammalian study review, the researchers concluded that the rigorous procedures developed for mammalian reproduction held promise for practical application in human embryonic stem cell (hESC) line production. Furthermore, they specifically proposed hESC research should steer away from attempting to produce viable offspring, focusing efforts on the use of cloned embryos as a viable source for deriving stem cell lines instead.
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Lanza was part of the team that cloned the world's first early stage human embryos, as well as the first to successfully generate stem cells from adults using somatic-cell nuclear transfer (therapeutic cloning). Lanza demonstrated that techniques used in preimplantation genetic diagnosis could be used to generate embryonic stem cells without embryonic destruction. In 2001, he was also the first to clone an endangered species (a Gaur), and in 2003, he cloned an endangered wild ox (a Banteng) from the frozen skin cells of an animal that had died at the San Diego Zoo nearly a quarter-of-a-century earlier. Lanza and his colleagues were the first to demonstrate that nuclear transplantation could be used to reverse the aging process and to generate immune-compatible tissues, including the first organ grown in the laboratory from cloned cells.
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Genetics In Medicine. Elsevier. pp. 123–125. . or by epigenetic regulation, alterations to DNA such as methylation that do not involve changes in the DNA coding sequence. A mutation in an allele acquired by a somatic cell early in its development can be passed on to its daughter cells, including those that later specialize to gametes. With such mutation within the gamete cells, a pair of medically typical individuals may have repeated succession of children who suffer from certain genetic disorders such as Duchenne muscular dystrophy and osteogenesis imperfecta because of germline mosaicism. It is possible for parents unaffected by germline mutations to produce an offspring with an autosomal dominant (AD) disorder due to a random new mutation within one’s gamete cells known as sporadic mutation; however, if these parents produce more than one child with an AD disorder, germline mosaicism is more likely the cause than a sporadic mutation.
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China has one of the most unrestrictive embryonic stem cell research policies in the world. In recent years, seeing the research opportunities that China's lax regulations provide, many expatriate Chinese scientists from the West are returning to China to establish stem cell research centers and laboratories there. As a result of the increased interest in this field of research, in 2003, the People's Republic of China Ministry of Science and Technology and Ministry of Health issued official ethical guidelines for human embryonic stem cell research in its territories. The guidelines strictly forbid any research aimed at human reproductive cloning and require that the embryos used for stem cell research come only from: # Spared gamate or blastocyst after in vitro fertilization (IVF) procedures; # Fetal cells from accidental spontaneous or voluntarily selected abortions; # Blastocyst or parthenogenetic split blastocyst obtained by somatic cell nuclear transfer technology; or # Germ cells voluntarily donated.
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A primary goal in embryomics is a complete mapping the embryogenic tree: Identifying each of the cell types present in the developing embryo and placing it in the tree on its proper branch. There is an unknown number, probably thousands, of distinct cell types present in the developing embryo, including progenitor cell lines which are only temporarily present and which disappear either by differentiating into the permanent somatic cell types which make up the tissues of the infant's body at birth (or into other progenitor cell lines), or by undergoing the programmed cell death process known as apoptosis. Each cell type is defined by which genes are characteristically active in that cell type. A particular gene in a cell's genome codes for the production of a particular protein, that is, when that gene is turned on (active), the protein coded for by that gene is produced and present somewhere in the cell.
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Lewis and her husband helped develop and put into practice the first experimental systems for observing and understanding somatic cell physiology in complex organisms, which demonstrated that the behavior of these autonomous cells had a significant relationship to the development, infection, immunity, physiology and development of cancer for the organism. As a result, their work served to establish the importance of cellular behavior. As a result, this couple’s greatest impact on embryology and cell biology in the twentieth century was teaching later generations of biologists the basic factors involved in tissue culture based on what they had learned from their research. The Lewises saw a place for the findings on the cell related to embryology as well, and expressed this perspective to the president of the Carnegie Institution of Washington when they wrote to him that knowing the extent of a cell’s permanent individuality must be determined before it is possible to understand how they cooperate and are integrated into a tissue.
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The centralised procedure allows companies to submit a single application to the agency to obtain from the European Commission a centralised (or 'Community') marketing authorisation (MA) valid in all EU and European Economic Area (EEA)-European Free Trade Association (EFTA) states (Iceland, Liechtenstein and Norway). The centralised procedure is compulsory for all medicines derived from biotechnology and other high-tech processes, as well as for human medicines for the treatment of HIV/AIDS, cancer, diabetes, neurodegenerative diseases, auto-immune and other immune dysfunctions, and viral diseases, and for veterinary medicines for use for growth or yield enhancers. It is also compulsory for advanced-therapy medicines such as gene- therapy, somatic cell-therapy or tissue-engineered medicines and for Orphan medicines (medicines for rare diseases). The centralised procedure is also open to products that bring a significant therapeutic, scientific or technical innovation, or is in any other respect in the interest of patient or animal health.
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In the United States, scientists at the Harvard Stem Cell Institute, the University of California San Francisco, the Oregon Health & Science University, Stemagen (La Jolla, CA) and possibly Advanced Cell Technology are currently researching a technique to use somatic cell nuclear transfer to produce embryonic stem cells.Elizabeth Weise, "Cloning race is on again", USA Today (January 17, 2006, retrieved October 6, 2006) In the United Kingdom, the Human Fertilisation and Embryology Authority has granted permission to research groups at the Roslin Institute and the Newcastle Centre for Life."Dolly scientists' human clone bid", BBC News (September 28, 2004, retrieved October 6, 2006) SCNT may also be occurring in China.Charles C. Mann, "The First Cloning Superpower", Wired (January 2003, retrieved October 6, 2006) In 2005, a South Korean research team led by Professor Hwang Woo-suk, published claims to have derived stem cell lines via SCNT, but supported those claims with fabricated data.
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Brown’s research is directed to the X-chromosome inactivation process in humans. Her lab has identified critical differences between mouse and human X-chromosome inactivation, such as the absence of paternal X inactivation in human extraembryonic tissues, the higher proportion of human “escapees” and the identification of different regulatory sequences of human XIST and mouse Xist. Her lab has been cataloging escape genes using both expression and DNA methylation analysis r to determine which genes contribute to sex differences in disease susceptibility, and which regions of DNA are susceptible to, or resistant to, epigenetic gene silencing. Since human embryonic stem cells are epigenetically unstable, Brown and colleagues have developed alternative model systems to study human inactivation, including inducible XIST transgenes in human somatic cells, human somatic cell hybrids retaining the active or the inactive X chromosome, and mouse cells with X-linked transgenes of human DNA. Her lab collaborates with other research groups at the B. C. Children’s Hospital and the BC Cancer Agency to investigate the clinical relevance of X-linked inactivation and expression in disease predisposition, cancer progression, and X-linked diseases, chromosome rearrangements and aneuploidies.
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