Scientists at the University of California,
Davis, have successfully produced a bull calf,
named Cosmo, who was genome-edited as an embryo
so that he’ll produce more male offspring.
The research was presented at the American
Society of Animal Science meeting.
Using the genome-editing technology CRISPR,
researchers can make targeted cuts to the
genome or insert useful genes, which is called
a gene knock-in.
In this case, scientists successfully inserted
or knocked-in the cattle SRY gene, the gene
that is responsible for initiating male development,
into a bovine embryo.
It’s the first demonstration of a targeted
gene knock-in for large sequences of DNA via
embryo-mediated genome editing in cattle.
The scientists anticipate Cosmo’s offspring
that inherit this SRY gene will grow and look
like males, regardless of whether they inherit
a Y chromosome.
The motivation to produce more male cattle
is that male cattle are about 15 percent more
efficient at converting feed into weight gain.
They are more fuel-efficient than females.
Additionally, they tend to be processed at
a heavier weight.
It could also be a win for the environment,
with fewer cattle needed to produce the same
amount of beef.
As the Food and Drug Administration regulates
gene-editing of animals as if they were drugs,
Cosmo and his offspring will not enter the
food supply.
