By Sarah Kaplan
Your Neanderthal DNA might actually be doing you some good
But most human traits come from a complex combination of genes, making it a lot more difficult to figure out exactly what makes the inherited genetic material beneficial.
“For a lot of these selection scans you can speculate based on the gene function but the actual adaptive reason is much harder to understand,” said Racimo, who was a PhD student at the University of California at Berkeley at the time of the study.
Racimo has his suspicions about the benefits of two of the genes he and his colleagues discovered: These variants are found in Native American, Eurasian and Denisovan populations and have to do with the production of fat tissue.
“We have an idea of what they are doing,” he said, cagily. But those findings are due to be published in another paper, so he couldn’t say more.
The main takeaway from the study, Racimo said, is that we owe more to our Neanderthal and Denisovan relatives than we think. For years, conventional wisdom about these archaic humans is that they were weaker, dumber and less evolutionarily fit than modern humans and that’s why they died out. But Racimo believes that other hominid species could have actually helped humans.
“Archaic humans expanded out of Africa before modern humans, so they had a lot more time to adapt to the particular conditions of Europe and Asia,” he said. “A shortcut to adapt to these conditions, instead of waiting for the mutations to occur, is to obtain the genetic material from these archaic human groups who were established for a long time.”
For example, the genes associated with immunity may have helped Homo sapiens resist the new pathogens they encountered as they spread around the globe.
Lest you start feeling too warm and fuzzy about ancient human-Neanderthal relations, this issue of Molecular Biology and Evolution contains a study looking at another portion of our archaic inheritance: genital warts. According to a genetic analysis of HPV16, a strain of Human Papillomavirus, the disease was likely passed to modern humans who had sex with Neanderthals or Denisovans after leaving Africa.
You win some, you lose some.