Three years ago, scientists thought humans had never had sex with Neanderthals. Last year, they changed their tune—and now it looks like DNA passed down from Neanderthals has had a “profound impact” on our immune systems. Scientists compared a section of the modern human genome to the same area in the genomes of Neanderthals and another ancient hominid, the Denisovans, the Los Angeles Times reports.
The genome region they studied contained HLA genes, which guide the creation of proteins that detect cell abnormalities. The researchers discovered that in Europeans, more than half the genetic variants in one of the genes were traceable to ancient genomes. In Asians, some 70% of the variants appeared to come from the early hominids, while in those from Papua New Guinea, the figure was as high as 95%. “We expected we'd see some, but the extent that these contributed to the modern (genomes) is stunning,” said a study author.