Two daddies : baby mice created in the laboratory only from male cells

 

Could male couples one day have a biological child together ? We are still very, very far from that. But one lab managed to do it with mice.

This is a new genetic advance. Researchers have announced that they have succeeded in creating healthy and fertile mice from male cells only, which was impossible until now, reports the journal Nature. But there are still important advances to be made and ethical questions to be asked before such manipulation can one day be applied to humans in the medical field.

Biologist Katsuhiko Hayashi of Osaka University, Japan, has been working on the issue for years. Already in 2018, mouse eggs had been successfully formed by his team from mice of the same sex. While cubs with two mothers survived to adulthood and were fertile, those with two fathers lived only a few days.

Transforming an XY cell into XX, a feat

Five years later, at the International Summit on Human Genome Editing in London, held on March 8, the Japanese professor presented the latest feat of his laboratory. Scientists set out to create eggs from cells taken from adult male mice. They managed to change the chromosomes of some of the male cells from XY to XX. From these cells, they were then able to make oocytes (female eggs) and fertilize the other male cells. Eggs fertilized and implanted into female mice resulted in the birth of several mice with two biological fathers.

The survival rate of the experiment, however, was low. Out of 630 embryos transferred, only seven mice developed. But the babies grew normally and were fertile as adults, the biologist said.

Treating infertility issues and creating embryos for same-sex couples

The technique is far from applicable in humans at this time, and scientific study has yet to be peer reviewed. But the concept raises the possibility of one day treating some gene-related causes of infertility, or even creating single-parent or same-sex couple embryos. "This is a significant advance with important potential applications," Keith Latham, a biologist at Michigan State University, told the journal Nature.

Professor Hayashi's technology, described as "fascinating" but "provocative" by some of his colleagues, could be applicable to humans within a decade, he says. An assertion that other scientists strongly doubt. Already, human reproduction is much more complex. Moreover, six years after the success of his experimentation on mice born to two mothers, it is still not close to being reproduced in humans, in particular for ethical questions.