Chuck Bednar for redOrbit.com – @BednarChuck
Detailed genetic analysis of an ancient European jawbone has found evidence that the person had a close Neanderthal ancestor, suggesting that modern humans started interbreeding with the now-extinct species shortly after their first arrived on the continent.
An international team of researchers, including scientists from Harvard Medical School and the Max Planck Institute for Evolutionary Anthropology in Germany, reported their discovery after intently studying a 40,000-year-old jawbone from Romania – a specimen believed to be one of the earliest remains of a modern human yet discovered in Europe.
DNA from this human mandible, which was found in Oase Cave in Romania, revealed that six to nine percent of the individual’s genome had come from Neanderthals, more than any previously discovered human sequenced to date. On average, the Neanderthals contributed just one to three percent to the genomes of present-day European peoples.
Since such large portions of the individual’s chromosomes were of Neanderthal origin, the study authors believe that a Neanderthal was among his ancestors as recently as four to six generations back. The Neanderthals and the first humans got busy very quickly.
Pretty recent ancestor
“The data from the jawbone implies that humans mixed with Neandertals not just in the Middle East but in Europe as well,” said Qiaomei Fu, one of the lead authors of the study and a postdoctoral fellow at the Harvard Medical School Department of Genetics.
Fu and her colleagues estimated that 5 to 11 percent of the genome preserved in the bone derives from a Neanderthal ancestor, including, as she told redOrbit via email, especially large segments of chromosomes 4, 5, 6, 9, and 12. By estimating how the lengths of DNA inherited from an ancestor become shorter with each passing generation, they were able to estimate that the man had a Neanderthal ancestor within the previous four to six generations.
She explained to redOrbit via email that since the individual received a “large amount” of their chromosomes from a Neanderthal ancestors, she and her colleagues could “clearly identify” the ancestry that of “a fourth, fifth, or sixth degree relative.” In other words, she added, “this recent Neanderthal admixture occurred less than 200 years before the time he lived.”
However, in the case of the Romanian fossil, the Fu and her colleagues found that the individual “belonged to a population that did not contribute much, or not at all, to later Europeans,” which suggests that he was “a member of an initial early modern human population that interbred with Neanderthals, but did not contribute much to later European populations.”
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