Researchers in China have coaxed mice to produce offspring from same-sex parents, Scientific American reports. While some pups born to two female parents appear healthy, those with two male parents died shortly after birth, which Scientific American says underscores the challenges the approach faces.
A Chinese Academy of Sciences-led team relied on both stem cell and CRISPR gene editing approaches to develop their bimaternal and bipaternal mice, as they report in Cell Stem Cell. For bimaternal mice, they cajoled eggs to divide to isolate haploid cells. They then deleted three regions of the mouse genome to change their imprinting patterns. Those altered eggs were then injected into other oocytes and implanted into surrogate mice. About 14 percent of the pups lived to adulthood and were fertile, Discover's D-brief blog adds.
A slightly different approach had to be taken to attempt to generate bipaternal mice. After sperm was isolated, seven imprinted regions had to be deleted, and then it and another sperm were injected into an enucleated egg that was then implanted in a surrogate. Fewer of these pups, 2.5 percent, made it to full term and died shortly thereafter, D-brief notes.
"This shows us what's possible," senior author Wei Li from the Chinese Academy of Sciences tells the Guardian.
It also, Harvard Medical School's Yi Zhang, tells Scientific American, addresses basic questions about the role of epigenetics in reproduction. "From a scientific point of view, even for mice this is very difficult," he adds. "And for primates and humans, it's going to be 10 times more difficult."