Started by stromboli, September 02, 2014, 12:24:35 PM
QuoteFor one woman, pregnancy was not enough to prove motherhood.After taking a DNA test, Lydia Fairchild of Washington State was shocked to find that she was not the mother of her own children â€" the same children that she remembered conceiving, carrying and giving birth to. What had gone wrong?As a struggling single mother of two with a third child on the way, Fairchild, then 26 years old, decided to apply for government assistance. In order to qualify, Fairchild was required to undergo DNA testing to prove that she was the mother of children for whom she was claiming. When the test results came back, her world was shattered by an incredible revelation â€" she was not the mother of her two children. Now facing criminal charges for fraud, Fairchild was ordered to have a court representative be present at the birth of her third child for an immediate DNA test, which revealed the same results.Further DNA analysis showed that Fairchild was more like an aunt to her children than a mother, but Fairchild didnâ€™t have a sister. Then, the discovery of a similar case in Boston brought to light another possibility. Thanks to a rare genetic condition, it turned out that Fairchild was a chimera â€" essentially a twin in her own body. Graham Noble of guardianlv.com has more on the condition:Those rare individuals, dubbed â€œChimerasâ€, had started out as twins; in the early stage of pregnancy, one of the twins had merged with â€" been absorbed by, one could almost say â€" the other twin. The cells of the consumed twin, however, did not disappear and remained alive in one concentrated area of their siblingâ€™s body. In essence, a human chimera is one person made up of two separate sets of genetic material; they are, in fact, their own twins.Fortunately, once Fairchild's condition was discovered, all charges were dropped and her case was dismissed.
QuoteChimera: In medicine, a person composed of two genetically distinct types of cells. Human chimeras were first discovered with the advent of blood typing when it was found that some people had more than one blood type. Most of them proved to be "blood chimeras" -- non-identical twins who shared a blood supply in the uterus. Those who were not twins are thought to have blood cells from a twin that died early in gestation. Twin embryos often share a blood supply in the placenta, allowing blood stem cells to pass from one and settle in the bone marrow of the other. About 8% of non-identical twin pairs are chimeras.Many more people are microchimeras and carry smaller numbers of foreign blood cells that may have passed from mother across the placenta, or persist from a blood transfusion. In vitro fertilization (IVF) is also contributing to the number of human chimeras. To improve success rates, two or more embryos are placed in the uterus so women who have IVF have more twin pregnancies than usual. More twins mean more chimeras.In Greek mythology, the Chimera was an awesome fire-breathing monster with the head of a lion, the body of a goat, and the tail of a serpent. The Chimera was killed by the hero Bellerophon mounted, in most versions of the tale, on Pegasus, the winged horse.