![]() Don’t forget that all human females are mosaics, too, with portions of their bodies expressing one X chromosome, and other portions expressing the other. One worry for me is the home DNA tests that are available and the statistics they claim as accurate, sure there may have been some divorces as results that the tests showed that the father was not a true parent when he was, and also cases where the father wanted custody but DNA tests have shown him not to be the father when he was.īryan Lowder said: “Fascinating article, Cynthia. Scarey stuff as suggested above where guilty parties can be tested as not guilty in some cases. The conclusion, I believe, was that the blood carried one type of DNA but separate hairs can contain the 2 types of Dna, and organs can contain tissue with both types of DNA but one type being more prevalent than the other. The maternity case was proven in the end when the woman gave birth to her third baby, both mother and baby were tested immediately after the birth and the DNA tests indicated that she was NOT the mother, which of course was impossible. After all, if Jane’s genetic anomaly had appeared in the father rather than the mother, it is not only possible, but probable, that the first obvious explanation would have been the only one considered, and the affair would have been one for divorce court rather than the New England Journal of Medicine.Ī very interesting article Celia, having just watched the programme that appears to be the one Dyson spoke of I sought more information. Given that, it is entirely possible that there are many more chimeras in existence. ![]() However, most chimeras are unaware of their condition until some anomaly brings it to light. This sort of mosaicism is exceedingly rare in the medical annals, with fewer than 100 cases documented world-wide. While this is a dramatic finding, most chimeras show more subtle signs, such as mismatched eye colors, or parti-colored hair. Their patient was a chimera formed from the fusion of male and female embryos. Instead they found something quite unexpected, an ovary and a fallopian tube. However, when they examined him they could not find a second testicle. Doctors at the University of Edinburgh in 1998 had a patient referred to them for an undescended left testicle. Many human chimeras show no overt signs of their condition, but some exhibit more obvious physical signs. She would, however, probably be a poor candidate as a kidney donor, her organs twice as likely to be rejected. Interestingly, this genetic oddity gives her a better-than-usual chance of having a successful kidney donation, as her immune system sees two distinct tissue types as non-foreign. The cheek cells from which the genetic testing was done were from one of those embryos, but at least some of the cells in her ovaries came from the other. The cells in her body are a mosaic of genes from both of the original embryos. Rather than a simple exchange of blood, it was found that she and her fraternal twin merged in utero, leaving only one fetus. Up to 8% of fraternal twins are blood chimeras. Each twin is genetically separate except for their blood, which has two distinct sets of genes, and even two distinct blood types. Blood and blood-forming tissue is exchanged, and takes up residence in the bone marrow. This happens when fraternal twins share some portion of the same placenta. The most common form of human chimera is called a blood chimera. Animal chimeras, or mosaics, as they can also be called, don’t usually divide so neatly. There are chimera African violets, where the core of the plant is genetically distinct from the outer layers. In biology, the term has come to refer to any organism that contains more than one set of genes. The Chimera is primarily known as a creature of Greek legend – a fire-breathing monster with parts of a goat and a lion with a serpent for a tail. A mix-up of babies was ruled out, and Jane and her husband had not undergone in vitro fertilization, so it was absolutely clear that the children she had delivered were actually hers. Completely unexpectedly, two of her three children tested as genetically not hers. At the age of 52, when her children were full-grown, she and her children underwent genetic testing for a possible kidney transplant. Now, add a twist: What if such a discovery were made by the children’s mother? Suddenly the question becomes not “Who?” but rather “Huh?” Recriminations, marital troubles, and perhaps a divorce would be in order. Imagine if a man discovered one day that two of his three children were not genetically related to him. ![]()
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