The Neanderthal in My Family Tree
New genetic evidence shows our ancestors interbred with now-extinct species.
"Either our ancestors had just a few hookups, perhaps as the first waves of modern humans moved into Neanderthal territory. Or, the two groups were well on their way to becoming separate species and, thus, were biologically incompatible and able to produce few offspring that survived and were fertile."
"a new character emerging from Siberia, of all places. Pääbo’s group published the nuclear genome of a new kind of archaic human from Denisova Cave in the Altai Mountains of Russia. The researchers had extracted remarkably well-preserved DNA from a tiny sliver of finger bone from a girl who lived in the cave more than 50,000 years ago. The DNA showed that she was neither a Neanderthal nor a modern human (although bones of both species have been found in the same cave at different times). She belonged to a new lineage called the Denisovans."
"Although only three fossils of Denisovans have been found so far (the finger bone and two molars in the same cave), the girl belonged to a group that left its mark on living people today in Southeast Asia. In follow-up studies, researchers identified people who had inherited about 3 percent of their DNA from the Denisovans, as well as 4 percent to 6 percent of their DNA from Neanderthals. These people are found in a patchwork quilt of populations on islands of Southeast Asia, including Melanesians in Papua New Guinea, aboriginals in Australia, and Negritos in the Philippines. Researchers are searching for new fossils of Denisovans in Asia. But for now, they’re in the curious position of having a genome in search of a substantive fossil record of this new kind of human."http://www.slate.com/articles/health_and_science/human_evolution/2012/10/neanderthal_and_denisovan_genetics_human_ancestors_interbred_with_extinct.html