Do you want a male or a female?

A new study by Tel Aviv University has revealed a genetic system that allows mammals to produce exclusively females.

The shift in the sex ratio of various organisms, including plants, insects, crustaceans and fish, has been demonstrated many times using genetic and non-genetic methods, but they were not applicable to mammals.

A new study shows that when using the intersection of two genetically modified lines, only female offspring can be obtained. To obtain similar results, scientists crossed two types of genetically engineered mice. On the maternal side, a functional protein was encoded using the CRISPR/Cas9 gene editing system, which is inactive if not controlled by special guide (guide) RNAs, in turn encoded on the paternal side in the Y chromosome. After fertilization, the guide RNA from the paternal sperm and the Cas9 protein from the maternal egg were combined in male embryos, but not in female embryos (since females lack a Y chromosome). This combination of guide RNAs with Cas9 destroys male embryos.

A drawing from an article in EMBO reports.

The concept has been proven in mice, but it can also be demonstrated in cattle, pigs, goats, chickens and other animals.

Farmers in the dairy and poultry industries obviously prefer females, but until now there was no available genetic way to regulate the sex ratio.

It is important to note that this system can also be used to "produce" males. The development of RNA guides on the paternal X chromosome should lead to the elimination of females, which in turn will lead to offspring consisting only of males, which is more profitable in the meat industry.

Article by Yozef et al. A genetic system for biasing the sex ratio in mice is published in the journal EMBO reports.

Elena Panasyuk, portal "Eternal youth" http://vechnayamolodost.ru /