thrakomakedones
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Mέλος από: Nov 04, 2006
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 Στάλθηκε: Σάββατο 4 Νοε 2006, 20:53 GMT Τίτλος Μηνύματος: Genetically-Engineered humans have already been born |
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The earthshaking news appeared in the medical journal Human Reproduction under the impenetrable headline: "Mitochondria in Human Offspring Derived From Ooplasmic Transplantation." The media put the story in heavy rotation for one day, then forgot about it. We all forgot about it.
But the fact remains that the world is now populated by dozens of children who were genetically engineered. It still sounds like science fiction, yet it's true.
In the first known application of germline gene therapy — in which an individual's genes are changed in a way that can be passed to offspring — doctors at a reproductive facility in New Jersey announced in March 2001 that nearly 30 healthy babies had been born with DNA from three people: dad, mom, and a second woman. Fifteen were the product of the fertility clinic, with the other fifteen or so coming from elsewhere.
The doctors believe that one cause for failure of women to conceive is that their ova contain old mitochondria (if you don't remember your high school biology class, mitochondria are the part of cells that provides energy). These sluggish eggs fail to attach to the uterine wall when fertilized.
In order to soup them up, scientists injected them with mitochondria from a younger woman. Since mitochondria contain DNA, the kids have the genetic material of all three parties. The DNA from the "other woman" can even be passed down along the female line.
The big problem is that no one knows what effects this will have on the children or their progeny. In fact, this substitution of mitochondria hasn't been studied extensively on animals, never mind homo sapiens. The doctors reported that the kids are healthy, but they neglected to
mention something crucial. Although the fertility clinic's technique resulted in fifteen babies, a total of seventeen fetuses had been created. One of them had been aborted, and the other miscarried. Why? Both of them had a rare genetic disorder, Turner syndrome, which only strikes
females. Ordinarily, just one in 2,500 females is born with this condition, in which one of the X chromo-somes is incomplete or totally missing. Yet two out of these seventeen fetuses had developed it.
If we assume that nine of the fetuses were female (around 50 percent), then two of the nine female fetuses had this rare condition. Internal documents from the fertility clinic admit that this amazingly high rate might be due to the ooplasmic transfer.
Even before the revelation about Turner syndrome became known, many experts were appalled that the technique had been used. A responding article in Human Reproduction said, in a dry understatement: "Neither the safety nor efficacy of this method has been adequately investigated." Ruth Deech, chair of Britain's Human Fertilization and Embryology Authority, told the BBC: "There is a risk, not just to the baby, but to future generations which we really can't assess at the moment."
The number of children who have been born as a result of this technique is unknown. The original article gave the number as "nearly thirty," but this was in early 2001. At that time, at least two of the mutant children were already one year old.
Dr. Joseph Cummin, professor emeritus of biology at the University of Western Ontario, says that no further information about these 30 children has appeared in the medical literature or the media. As far as additional children born with two mommies and a daddy, Cummin says that a
report out of Norway in 2003 indicated that ooplasmic transfer has been used to correct mitochondrial disease. He opines: "It seems likely that the transplants are going on, but very, very quietly in a regulatory vacuum, perhaps." |
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