Researchers from the University of Missouri have been using the CRISPR-Cas9 genome editing approach to breed pigs that are resistant to porcine reproductive and respiratory syndrome virus (PRRSV), Scientific American reports.
Typically, the virus sickens the pigs and may lead to miscarriage or death, and vaccinations haven't been able to stop the spread of the virus. But by creating pigs with defective CD163 proteins, which are thought to mediate the viruses' entry into cells, the researchers found that the edited pigs were resistant to a PRRSV isolate, as they reported recently in Nature Biotechnology. Unedited pigs, meanwhile, fell ill.
"I expected the pigs would get the virus but not get as sick," senior author Randall Prather tells Scientific American. "But it is just night and day. The pigs are running around with the other pigs coughing on them, but they are just fine."
Alison Van Eenennaam, a geneticist at the University of California, Davis, adds that other farm animals will likely be developed through genome editing.
"This is analogous to breeding," she tells Scientific American. "It's just precision breeding."