Sherpas from Nepal and Tibet are known for their unique ability to thrive in high-altitudes, most famously Mount Everest. Scientists believe that this adaptation was acquired over time by interbreeding with the now extinct humans known as Denisovans. A new study from the Shanghai Institutes for Biological Sciences believes that Tibetan Mastiffs may have followed a similar path.
Like their human counterparts, Tibetan Mastiffs can also live in regions most others can’t—in the thin mountain air above 4,000 meters. The lead researcher and geneticist, Zhen Wang, believes that similar to people, this ability was acquired by interbreeding with gray wolves that already lived at high altitudes more than 20,000 years ago.
This breeding allowed the mastiffs to produce less hemoglobin, the protein that carries oxygen in red blood cells. This helps the dogs avoid clots and stokes that can arise when the body produces additional red blood cells in an effort to acquire more oxygen at high altitude. Scientists believe the gene responsible for the adaptation is called EPAS1, which regulates the production of hemoglobin, but weren’t sure how the mastiffs acquired it.
Zhen and his team suspected that the source was gray wolves since they had the EPAS1 gene and had lived on the Tibetan Plateau for some time. So they analyzed segments of DNA containing the gene from 29 canines, including Chinese highland and lowland gray wolves, Tibetan Mastiffs, Chinese lowland village dogs, and a golden jackal. As it turns out, Tibetan Mastiffs are much more closely related to other Chinese dogs than than gray wolves, but they found two genetic areas in the mastiffs that had signs of interbreeding with the Tibetan gray wolf. While the mastiffs got a useful adaptation out of the deal, there’s no genetic evidence that the wolves got anything beneficial in return.
Either way, it’s very cool to see dogs and humans adapt in a similar way!