Researchers analysing DNA from a 37,000 to 42,000-year-old human jaw bone say that the early modern human to whom it belonged - the oldest known modern human in Europe - had a Neanderthal ancestor who lived just 4 to 6 generations back in the individual's family tree.
     The jawbone was originally found in 2002 in south-western Romania, in a cave called Petera cu Oase, along with the skull of another individual. No artefacts were discovered nearby. The jawbone partly resembled those of modern humans, but some Neanderthal traits were also apparent.
     "I could hardly believe it when we first saw the results," said study co-leader Svante Paabo of the Max Planck Institute for Evolutionary Anthropology in Leipzig. "It is such a lucky and unexpected thing to get DNA from a person who was so closely related to a Neanderthal."
     David Reich, study co-leader and Howard Hughes Medical Institute (HHMI) investigator at Harvard Medical School, says: "The sample is more closely related to Neanderthals than any other modern human we've ever looked at before. We estimate that six to nine percent of its genome is from Neanderthals. This is an unprecedented amount. Europeans and East Asians today have more like two percent."
     "We know that before 45,000 years ago, the only humans in Europe were Neanderthals. After 35,000 years ago, the only humans in Europe were modern humans. This is a dramatic transition," Reich explains.
     All present-day humans who have their roots outside sub-Saharan Africa carry one to three percent of Neanderthal DNA in their genomes. Until now, researchers have thought it most likely that early humans coming from Africa mixed with Neanderthals in the Middle East around 50,000 to 60,000 years ago, however radiocarbon dating of remains from sites across Europe suggests that modern humans and Neanderthals both lived in Europe for up to 5,000 years. Changes in tool making technology, burial rituals, and body decoration imply a cultural exchange between the groups. "But we have very few skeletons from this period," Reich reveals.
     The Oase individual is not responsible for Neanderthal ancestry in present day humans. Reich says: "There may have been a pioneering group of modern humans that got to Europe, but was later replaced by other groups."

Edited from Popular Archaeology (22 June 2015)