A team of researchers from the Francis Crick Institute and the University of Kent have used the CRISPR gene editing system to produce litters of mice of a single sex, either all males or all females. Thanks to popular gene editing technology.
The fact that this experiment has been 100% successful is great news, as either in agriculture or in scientific experimentation, many times a single sex surplus of the animal is required, which could help prevent unnecessary slaughter. of animals that do not have the desired sex.
This new method uses the two-part genetic system to inactivate embryos shortly after fertilization. This inactivation allows the development of sex that is exclusively needed. As the scientists pointed out, such a gene-editing method could dramatically reduce sacrifice in both industries.
The Top1 gene is essential for DNA replication and repair. The scientists focused primarily on this gene. When an embryo was formed from a sperm and an egg, each containing half CRISPR-Cas9, gene editing was triggered in the embryo and it failed to develop beyond a very early stage of around 16 to 32 cells. . The scientists produced a male-only litter by editing the father’s X chromosome. On the other hand, they edited the Y chromosome to create an exclusively female litter. This new method did not cause a 50% decrease in the number of offspring produced, but the litter size was between 61% and 72% of the control litters, since the mice produce more eggs than necessary during each ovarian cycle.
This means that in situations where a specific sex is required, fewer breeding animals will be needed to produce the same number of offspring of the desired sex.
“This method works when we divide the genome editing process in half, between a male and a female, and only when the two halves meet in an embryo through reproduction is it activated. Embryos with both halves cannot develop beyond the very early cellular stages “, explains Charlotte Douglas, leader of the work that publishes the journal Nature Communications.
In the experiment, the team raised 72 litters, 36 of each variation, and each pup born was of the desired sex. The gene edits had no harmful side effects on the health of the mouse pups born.
Referencia: Douglas, C., Maciulyte, V., Zohren, J. et al. CRISPR-Cas9 effectors facilitate generation of single-sex litters and sex-specific phenotypes. Nature Communications 12, 6926 (2021). DOI: 10.1038/s41467-021-27227-2
