Scientists create mice offspring with two fathers from male DNA
By Ansharah Shakil, April 17 2024—
New research has revealed that scientists in Japan have been able to create mice whose parents are biologically male by using cells of male mice to create eggs. The study, published in the peer-reviewed scientific journal Nature in March, was the result of work by a group of researchers at Osaka University, led by Katsuhiko Hayashi, a professor of genome biology.
In an earlier experiment, the researchers transformed female mouse skin cells into an egg. Here, the researchers used male mouse skin cells to turn them into induced pluripotent stem cells (IPSCs), cultured in the lab. Pluripotency refers to having more than one potential outcome. Pluripotent cells can become different types of cells through a kind of genetic engineering as developed by Shinya Yamanaka, a Nobel Prize-winning scientist.
Like male humans, male mice contain one X and one Y chromosome, which were converted into IPSCs in the experiment. Some of these IPSCs become “XO” cells by losing their Y chromosome. Cell division errors led to some of these XO cells developing two X chromosomes, something which could be increased by treating XO cells with a compound called reversine. Turning the XX cells into primordial germ cells, the researchers programmed the cells to become egg cells, which were implanted into a mouse uterus after fertilizing into sperm. The end result is the birth of seven mice with two fathers. These mice lack any abnormalities, have a healthy lifespan and are fertile.
After years of research and lab work, this proof-of-concept experiment could have immense impacts not only for the reproductive biology of animals, but for humans. For animals, this could mean helping to prevent the extinction of endangered species and assist in species conservation. For humans, this kind of experiment can’t be replicated as of now due not only to its low chance of success — only seven out of 630 attempts worked, with a success rate of only a little over one percent — but due to ethical considerations and issues. There are also obvious differences between humans and mice. For one, mice only experience pregnancy for three weeks. It’s unknown if the process could be replicated with human stem cells.
Yet the experiment raises the question of whether it could allow LGBT+ male couples or single fathers to be able to have a child without a female egg, or to help infertile women have children. It’s possible that the process could eventually be used with human eggs, and work on this would take at least 10 years according to Hayashi. Replicating this process is something Hayashi and his team are currently working on, and their current research has been a huge step forward in the field of reproductive biology.