British scientists say they have created human embryos containing DNA from two women and a man, the Associated Press reports.
The process would be used as part of an in-vitro fertilization procedure to create healthy embryos for couples who do not want to pass on genetic diseases to their children.
The research, funded by the British charity the Muscular Dystrophy Campaign, was presented at a scientific conference recently but has not been peer-reviewed or published in a scientific journal.
Patrick Chinnery, a professor of neurogenetics at Newcastle University who is involved in the research, described the research goal to the Associated Press, saying, "We are not trying to alter genes, we're just trying to swap a small proportion of the bad ones for some good ones."
The technique replaces genes in the mitochondria, the cell’s energy source. Genetic defects in the mitochondria can cause epilepsy, muscular dystrophy, strokes and mental retardation. Researchers used normal embryos created from one man and one woman, where the woman’s egg had defective mitochondria. They transplanted the embryo into an emptied egg donated from another woman with healthy mitochondria.
10 embryos were created using the techniques. They were killed after five days.
Because only trace amounts of a person’s genes come from the mitochondria, experts said it would be incorrect to say the embryos have three parents.
"Most of the genes that make you who you are are inside the nucleus," Chinnery said, according to the Associated Press. "We're not going anywhere near that."
Advocates of the procedure hope it will be considered a therapy for couples in a bill expected to be discussed in Britain’s House of Commons in March.