Scientists have created eggs for the first time using cells from male mice and have produced seven mice from two fathers, according to a study published on Wednesday and described by the researcher as “revolutionary.”
The proven technique is still far from being used in humans, also due to very low success rates and numerous ethical issues.
But this breakthrough allows us to imagine the consequences in the field of reproduction, with the possibility of a couple of men or even one man having a biological child without the help of a female egg.
The study, published in the journal Nature, is the result of research by a Japanese team of evolutionary biologists, Katsuhiko Hayashi at Kyushu University.
The team has already found a way to turn female mouse skin cells into an egg that can be used to give birth to healthy young mice.
This time, she did the same experiment on a male mouse, taking skin cells from her tail before turning them into so-called pluripotent stem cells. That is, they are able to transform into cells of any type.
As in humans, mouse male cells have XY pairs of chromosomes, while female cells have XX pairs.
During this process, the researchers obtained about 6% of the cells that lost the Y chromosome, which gives them a male character, and then duplicated the remaining X chromosome to get the XX pair, characteristic of a female subject.
Scientists create eggs for the first time using cells from male mice and get seven mice from two fathers (AFP / Archives – Inti Ocon)
The transformed cells were used to create eggs, fertilized with the sperm of male mice, and then implanted into the uterus of surrogate female mice.
– Ethical issues –
Seven puppies were born out of 630 trials resulting in a success rate of less than 1%. Puppies are healthy and fertile.
Mr. Hayashi, who presented his research last week at the 3rd International Human Genome Editing Summit in London, warned that there are still many hurdles to human experimentation.
Nitzan Gonen, director of the sex determination lab at Israel’s Bar-Ilan University, told AFP about the “groundbreaking study.”
According to Dr. Gonen, in theory, this method will allow a couple of two men to give birth to a child, one of whom will give sperm and the other an egg. One person could even provide sperm and an egg, which he says would be “a bit like cloning Dolly the Sheep,” the first mammal to be cloned from an adult cell in 1996.
Jonathan Byerle and Diana Laird, two reproduction and stem cell experts at the University of California, San Francisco, explained in Nature that nothing guarantees the success of an experiment using human stem cells.
But they called the study “an outstanding milestone in reproductive biology.” With potential use to save an endangered species that has only one breeding male left.
For his part, Nitzan Gonen considers the procedure “extremely inefficient” as 99% of the embryos do not survive.
This would be even more problematic in humans, as a gestation period of nine months compared to three weeks in mice increases the risk of failure. In addition to technical issues, there are ethical issues. “The ability to do something does not necessarily mean that you have to do it (…), especially when we are talking about the type of person,” commented the Israeli researcher.