Along with sperm, the in vitro procedure adds fresh mitochondria extracted from less mature cells in the same woman's ovaries. The hope is to revitalize older eggs with these extra "batteries." But the FDA still wants proof that the technique works and is safe.
Chris Nickels for NPR
The size of the brain of a chimpanzee (right) is considerably smaller than that of a human brain. Probably multiple stretches of DNA help determine that, geneticists say.
Science Photo Library/Corbis
Being able to insert the two man-made letters into DNA, alongside the usual four-letter alphabet, could teach old cells new tricks and lead to better drugs, researchers say.
courtesy of Synthorx
Botulism bacteria, or Clostridium botulinum, grow in poorly preserved canned foods, especially meat and fish. The microbe's toxin could be lethal as a bioweapon.
Dr. Phil Luton/Science Photo Library/Corbis
This mouse egg (top) is being injected with genetic material from an adult cell to ultimately create an embryo — and, eventually, embryonic stem cells. The process has been difficult to do with human cells.
James King-Holmes/Science Source
The research team used yeast chromosome No. 3 as the model for their biochemical stitchery. Pins and white diamonds in the illustration represent "designer changes" not found in the usual No. 3; yellow stretches represent deletions.
Erick Munoz stands by a photo of his wife, Marlise Munoz, at home in Fort Worth, Texas, on Jan. 3. She is being kept on life support in a local hospital against the family's wishes.
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