October 6th, 2012 by James Ayre
New research is confirming the previously put forward theory that groups of ‘modern humans’ interbred with Neandertals as they journeyed out of Africa, leaving behind some Neanderthal DNA in modern non-Africans.
For the research, scientists from Harvard and the Max Planck Institute created an estimate of when the last shared ancestors of modern Europeans and Neanderthals lived.
“When the Neandertal (Neanderthal) genome was sequenced in 2010 it revealed that people outside Africa share slightly (up to 4% according to current data) more genetic variants with Neandertals than Africans do. One scenario that could explain this observation is that modern humans mixed with Neandertals when they came out of Africa. An alternative, but more complex, scenario is that African populations ancestral to both Neandertals and modern humans remained subdivided over a few hundred thousand years and that those more related to Neandertals subsequently left Africa.”
“Dr. Sriram Sankararaman and colleagues measured the length of DNA pieces in the genomes of Europeans that are similar to Neandertals. Since recombination between chromosomes when egg and sperm cells are formed reduces the size of such pieces in each generation, the Neandertal-related pieces will be smaller the longer they have spent in the genomes of present-day people.”
The results this yielded place the estimate for the last time that Neandertals and modern humans last genetic material at between 37,000 and 86,000 years ago. This is well after the time that modern humans first appeared outside of Africa. The data clearly confirms that “Neanderthals (or their close relatives) had children with the direct ancestors of present-day people outside Africa.”
Image Credits: Elisabeth Daynes; Wikimedia Commons
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