Genetics Reveal How Sheep First Split from Goats Four Million Years Ago

Sheep and goats are closely related, but they split and became separate species about four million years ago. Now, scientists have cracked their genetic code and now know how sheep became a distinct species.

"Sheep were one of the first animals to be domesticated for farming and are still an important part of the global agricultural economy," said Alan Archibald, one of the researchers, in a news release. "Understanding more about their genetic make-up will help us to breed healthier and more productive flocks."

In order to find out a bit more about sheep, the researchers decoded the sheep's genome sequence for the very first time. They then compared the sheep's genes with those of other animals, including humans, cattle, goats and pigs. In the end, the scientists identified several genes associated with wool production, and even found genes that underpin the evolution of the rumen. The rumen is a specialized chamber of the stomach that breaks down plant matter to make it ready for digestion.

These traits in particular help separate sheep from goats. With their woolly fleece, sheep stand out against goats. And by studying the genes that underpin the evolution of the rumen, researchers now know how sheep are so well-suited to a diet of low quality grass and other plants.

So how will understanding the genetic make-up of sheep help farmers? The research could aid in the development of DNA testing to speed up selective breeding programs. This, in turn, could give farmers a leg up when it comes to improving their stocks. That's not all, either. The new study could give a better understanding when it comes to learning about the diseases that affect sheep. This could help keep domesticated sheep populations healthier, which would greatly aid farmers.

The findings are published in the journal Science.