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Human And Neanderthal Encounters Dated
To discover why Neanderthals are most closely related to people outside Africa scientists have estimated the date when Neanderthals and modern Europeans last shared ancestors
Credit: Wikipedia
When the Neanderthal genome was sequenced in 2010 it revealed that people outside Africa share slightly more genetic variants with Neanderthals than Africans do. One scenario that could explain this observation is that modern humans mixed with Neanderthals when they came out of Africa. An alternative, but more complex, scenario is that African populations ancestral to both Neanderthals and modern humans remained subdivided over a few hundred thousand years and that those more related to Neanderthals 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.
Credit: Wikipedia
The team estimate that Neandertals and modern humans last exchanged genes between 37,000 and 86,000 years ago, well after modern humans appeared outside Africa but potentially before they started spreading across Eurasia. This suggests that Neandertals (or their close relatives) had children with the direct ancestors of present-day people outside Africa.
This work was supported by the Presidential Innovation Fund of the Max Planck Society, the Krekeler Foundation, and the National Science Foundation (HOMINID grant 1032255). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
The authors have declared that no competing interests exist.
Contacts and sources:
Dr. Sriram Sankararaman
Public Library of Science
Citation Sankararaman S, Patterson N, Li H, Pääbo S, Reich D (2012) The Date of Interbreeding between Neandertals and Modern Humans. PLoS Genet 8(10):e1002947. doi:10.1371/journal.pgen.1002947 http://www.plosgenetics.org/doi/pgen.10029347
