A More Humane Livestock Industry, Brought to You by Crispr

Cow 401 and her herdmates were the product of two and a half years of research, Van Eenennaam’s attempt to create a strain of gene-edited cattle specially suited to the needs of the beef industry. Had everything gone as planned, all the calves in this experiment would have been born male—physiologically, at least. Like humans, cattle carry two sex chromosomes; those born XX are female, and those born XY are male. But it isn’t the Y that makes the man. It’s a single gene, called SRY, that briefly flickers to life as an embryo grows and instructs it to develop male traits. Using Crispr, Van Eenennaam’s team added a copy of SRY to the X chromosome too. That way, even if a cow was born genetically female, she’d be expected to appear male all the same. Since beef ranchers generally prefer males to females (more meat for the money), Van Eenennaam believed there could someday be a market for these Crispr’d animals.

More than that, though, the project was a proof of concept. One of Van Eenennaam’s goals is to make the raising of livestock not only more efficient but also more humane. If a calf’s sex could be altered with a copy-paste of a single gene, that might pave the way for all kinds of experimentation—and not only in the beef business. Although ranchers may prefer male animals, their colleagues in the egg and dairy industries favor females. Since bulls can’t make milk and roosters can’t lay eggs, it’s cheaper to destroy them than raise them to adulthood. But if you could ensure that only heifers and hens are born, the carnage wouldn’t be necessary.

…more…

https://www.wired.com/story/crispr-gene-editing-humane-livestock/