Neanderthals are still among us, Janet Kelso realized 8 years ago. She had helped make the momentous discovery that Neanderthals repeatedly mated with the ancestors of modern humans—a finding that implies people outside of Africa still carry Neanderthal DNA today. Ever since then, Kelso has wondered exactly what modern humans got from those prehistoric liaisons—beyond babies. How do traces of the Neanderthal within shape the appearance, health, or personalities of living people?
For years, evolutionary biologists couldn’t get their rubber-gloved hands on enough people’s genomes to detect the relatively rare bits of Neanderthal DNA, much less to see whether or how our extinct cousins’ genetic legacy might influence disease or physical traits.
But a few years ago, Kelso and her colleagues at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, turned to a new tool—the UK Biobank (UKB), a large database that holds genetic and health records for half a million British volunteers. The researchers analyzed data from 112,338 of those Britons—enough that “we could actually look and say: ‘We see a Neanderthal version of the gene and we can measure its effect on phenotype in many people—how often they get sunburned, what color their hair is, and what color their eyes are,’” Kelso says. They found Neanderthal variants that boost the odds that a person smokes, is an evening person rather than a morning person, and is prone to sunburn and depression. [Continue reading…]