A few genes may have put black snub-nosed monkeys on top of the world.
Black, or Yunnan, snub-nosed monkeys (Rhinopithecus bieti) live in high-altitude forests on a small slice of the Tibetan plateau. At 3,400 to 4,600 meters above sea level, the monkeys reside at higher elevations than any other nonhuman primate.
A genetic study of DNA from four of the five remaining species of snub-nosed monkeys in Asia has found 19 gene variations in black snub-nosed monkeys that might be responsible for their high life. One of those genes, called ADAM9, is more active in cancer cells in low-oxygen conditions. Tibetan yaks and chickens also have their own versions of the gene. The results suggest that natural selection favored changes to ADAM9 because they help snub-nosed monkeys and other animals survive low-oxygen environments.
Tibetan people have other adaptations to high altitudes, including one inherited from extinct human relatives called Denisovans.
The study also found that snub-nosed monkeys are less genetically diverse than humans or great apes, largely because of their small population sizes, researchers report August 23 in Molecular Biology and Evolution.