Healthy Mice Born From Same-Sex Parents For First Time Ever

Gene editing, despite some criticism it has been receiving, is offering a broad range of possibilities in previously difficult to approach areas of research, with many industry leaders and luminaries singing its praises.

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CRISPR, in particular, is offering a window into methods for controlling genetic mutations, while some other forms are being used in the treatment of genetic disorders in utero.

Perhaps due to its increasingly successful use in mammal test subjects, it is becoming clear that its application in the editing of human embryos, with the open support of countries like Japan, will become a reality very soon.

Another recent example of promising research in the field involves the birth of a pair of mice from bimaternal (two mothers) thanks to the efforts of a team of researchers at the Chinese Academy of Sciences.

To achieve the results, the team set out to test the notion of genomic imprinting, which centers around how DNA alters its behavior based on gender. 

What are the implications for humans?

For the researchers, this study is not about offering definitive answers, as much as it is about exploring the unknown. A success rate of 14% was achieved with bimaternal embryos, while the numbers are 2.5% for bipaternal embryos.

"This research shows us what's possible," said Dr.  Wei Li, who conducted the experiments, adding, "We saw that the defects in bimaternal mice can be eliminated and that bipaternal reproduction barriers in mammals can also be crossed."

Study co-senior author Qi Zhou, elaborated even further: "We were interested in the question of why mammals can only undergo sexual reproduction. We have made several findings in the past by combining reproduction and regeneration, so we tried to find out whether more normal mice with two female parents, or even mice with two male parents, could be produced using haploid embryonic stem cells with gene deletions."

Further research and development are needed before the results can be applied to human subjects which might help same-sex couples to have their own genetic babies. But the idea has now become a possibility.

Mapping out the future of gene editing in humans

The narrative which is emerging from the scientific community about gene editing in human embryos is based on healthy skepticism, with a range of reactions: some advocate avoiding it altogether, while others feel that the process should evolve naturally and not be rushed.

“When you reproduce, you really want every factor possible to have a good outcome,” said Allan Spradling, a reproductive biologist at the Carnegie Institution for Science in Baltimore, Maryland. 

“I don’t think it’s going to lead to people genetically having two mothers or two fathers as a routine thing. We don’t understand it well enough, and it might be too risky to take it that far.”

Details about the study appear in a paper, titled "Generation of Bimaternal and Bipaternal Mice from Hypomethylated Haploid ESCs with Imprinting Region Deletions", which was published on October 11th in the Cell Stem Cell journal.