Scientists at Oregon Health Sciences University have successfully created embryos containing DNA from one man and two women — a technique that is known as "three-person" in vitro fertilization.
The research, which was published in the journal Nature, could potentially help mothers who have rare genetic disorders have healthy children by preventing damaged DNA in the mitochronidria from being passed on by the mother. According to the United Mitochondrial Disease Foundation, one in 4,000 children born in the United States are affected by some version of mitochondrial disease. Many don’t live past age 4 or 5., and mutations can cause blindness, deafness, strokes, seizures and cardiovascular problems.
The three-person IVF technique uses eggs and sperm from IVF. Scientists take the nucleus from the mother's egg and put it into a donor egg that has healthy mitochondria and has had its own nucleus removed. This new egg is then fertilized with the father's sperm.
The new embryo contains the genes of the mother and the father plus a tiny bit of mitochondrial DNA from the donor egg.
The Oregon Health team took eggs from seven women who had volunteered to take part in the research. The scientists replaced the mitochondrial DNA in 65 of the eggs with donor mitochondira and then looked to see how well these fared over the next week or so.
They found tha the fertilization rate was similar to the 33 control eggs that had not been manipulated.. Those that did fertilize normally developed to blastocyst stage at a similar rae to the control embryos. IVF embryos are normally transferred to the mother's uterus after gorwing for five or six days into a blastocyst.
Researchers from Newcastle University in the UK have also studied three-person IVF with a different method using an already fertilized egg. The nuclei from the father's sperm and the mother's egg, which contain the parents' DNA, were removed to leave behind the faulty mitochondria, Then, the nuclei were put into a different woman's egg from which the nucleus had been removed, but which retained its mitochondria.
Three-person IVF is quite controversial and a long way from being used in humans.
October 24, 2012
Posted by Leigh Ann Woodruff