Japanese researchers have successfully used male mouse cells to create eggs, marking a significant breakthrough in reproductive biology.
The process, which produced seven offspring from two father mice, was documented in the journal Nature.
The team of scientists, led by biologist Katsuhiko Hayashi of Osaka University and Kyushu University, took skin cells from a male mouse’s tail and turned them into induced pluripotent stem cells, which can be transformed into any cell type. Such a procedure causes around 6% of the cells to lose their Y chromosome and leave only an X chromosome, which is known as XO.
The scientists then duplicated the existing X chromosome in these cells to create an XX set by using a fluorescent protein and a drug called reversine.
The team was able to develop eggs out of these cells and fertilize them with the sperm of another male mouse. Female mice were used as surrogates for the fertilized eggs.
The experiment yielded a success rate of just over 1% as the seven mice they were able to produce were born after 630 attempts.
The process shows remarkable promise given that the resulting offspring are fertile and do not show any signs of abnormalities.
Nevertheless, Hayashi has cautioned that the technology is still limited and needs to address significant challenges, such as inefficiency, before it can be adapted to humans.
Another major concern is potential genetic mutations or errors made in the lab during egg creation, which can lead to serious health problems in newborns.
This means the prospect of one day enabling gay male couples or single men to have a biological child without the need for an egg from a woman is still far off.
In 2018, Chinese scientists were able to create mice offspring using DNA from two groups of mice parents of the same gender, a “mothers-only” group and a “fathers-only” group, using gene-editing technology.
The “mothers-only” mice, which required a simpler technique of injecting edited stem cells directly into the egg, had more promising results than the “fathers-only” batch, which needed a more complicated procedure. The male group’s process involved injecting edited embryonic stem cells from one father into an egg cell alongside sperm from a second father.
The female batch was able to produce 29 healthy mice, while the male batch produced 12 mice that exhibited “gruesome genetic mutations” and died just 48 hours later.