Neanderthal inheritance helped humans adapt to life outside of Africa
Phys.org / November 10, 2016
Excerpt: All told, the new study identifies 126 different places in the genome where genes inherited from those archaic humans remain at unusually high frequency in the genomes of modern humans around the world. We owe our long-lost hominid relatives for various traits, and especially those related to our immune systems and skin, the evidence shows.
“Our work shows that hybridization was not just some curious side note to human history, but had important consequences and contributed to our ancestors’ ability to adapt to different environments as they dispersed throughout the world,” says Joshua Akey of University of Washington School of Medicine in Seattle.
While the vast majority of surviving Neanderthal and Denisovan sequences are found at relatively low frequencies (typically less than 5%), the new analyses turned up 126 places in our genomes where these archaic sequences exist at much higher frequencies, reaching up to about 65%. Seven of those regions were found in parts of the genome known to play a role in characteristics of our skin. Another 31 are involved in immunity.
“The ability to increase to such high population frequencies was most likely facilitated because these sequences were advantageous,” Akey explains. “In addition, many of the high-frequency sequences span genes involved in the immune system, which is a frequent target of adaptive evolution.”
Generally speaking, the genes humans got from Neanderthals or Denisovans are important for our interactions with the environment. The evidence suggests that hybridization with archaic humans as our ancient ancestors made their way out of Africa “was an efficient way for modern humans to quickly adapt to the new environments they were encountering.”