Cattle Genes Edited with CRISPR Will Produce More Male Offspring

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In April 2020, scientists from the University of California witnessed the birth of a calf named Cosmo. When the calf was an embryo, its genome was edited. Thus, more males could produce offspring.

The team used the CRISPR gene-editing tool, they added a gene called SRY. This gene initiates male development and increases the likelihood that the animal’s offspring will become male.

Ideally, the SRY gene could be placed on the X chromosome. That way, Cosmo would produce 100 percent male offspring. However, that didn’t work, so they chose chromosome 17 instead.

This results in converting those who would normally be women to around 75% male. As an added advantage, chromosome 17 is a safe harbor region, so splicing does not disrupt neighboring genes.

“We anticipate that Cosmo’s offspring will inherit this SRY gene on the Y chromosome, resemble and appear to be males,” study author Alison Van Eenennaam said. says.

So why do researchers want to prioritize male cattle?

As it is a numbers game in the beef industry, men are 15% more efficient at converting feed to weight. This means more meat per animal at a lower cost. There may also be some environmental benefits, as less beef is required to produce the same amount of beef.

Of course, how well everything works will not be known for quite some time. Cosmo will not yet reach sexual maturity for another year and after that, it will take several pregnancies to confirm the rate.

And because the FDA has strict regulations on food regulated by CRISPR, Cosmo and his children will not enter the food supply.

CRISPR has been used in the past to edit all kinds of animal genomes for various purposes.

The scientists designed mice to find new ways to treat pigs or diseases to fight swine flu or to have lower body fat, lizards to become albino, mosquitoes that do not spread disease or diseases.