viernes, 9 de diciembre de 2016

Tibetan dogs can survive at high altitudes, thanks to ancient breeding with wolves


Credit: Zhen Wang, Shanghai Institutes for Biological Sciences, ChineseAcademy of Sciences, Shanghai, P. R. China

Tibetan mastiffs thrive where most dogs and people can’t: in the thin, frigid mountain air above 4000 meters. A new study suggests they acquired this talent by interbreeding with gray wolves that already ranged to such heights more than 20,000 years ago. Intriguingly, Tibetan people received their high-altitude fitness via the same mechanism—by interbreeding with now extinct humans known as Denisovans. The study adds to growing evidence that such ancient mating events have sometimes played a vital role in the adaptation of modern species to their environments, the scientists say.

“It’s a very cool discovery … which turns out to be a mirror of what’s going on with the humans [there],” says Elaine Ostrander, a geneticist at the National Institutes of Health in Bethesda, Maryland, who was not involved with the study.

An early type of dog from China’s lowland regions likely traveled to the Tibetan Plateau with people about 24,000 years ago, says study author Zhen Wang, a geneticist at the Shanghai Institutes for Biological Sciences in China. And like those humans, the lowland dogs “adapted in a relatively short time” to the high life, ultimately becoming today’s shaggy, large-boned mastiffs. During that transition, they acquired various traits that helped them endure the harsh, icy winters and limited supply of oxygen. [...] Science | AAAS / Link 2