Neanderthal lineages excavated from modern human genomes

Research has shown that a substantial fraction of the Neanderthal genome exists in modern human populations. Resent research analysing whole genome sequencing data from people from Europe and East Asia shows that 20% of Neanderthal DNA exists in this group. Previous research shows that someone of non-African descent may have inherited 1-3% of their genome from Neanderthal ancestors, so this is a big increase! The results are an excellent start to understanding the position of specific pieces of Neanderthal DNA in modern humans.

University of Washington scientists Benjamin Vernot and Joshua M. Akey, reported their results on January 29th in Science Express.  To check the accuracy of their findings they compared the Neanderthal sequences they found in modern humans to the recently mapped Neanderthal genome obtained by DNA recovery from fossilised bone. The results indicate that significant DNA sequences may be obtained from extinct groups even in the absence of fossilised remains, because these ancient sequences might have been inherited by other individuals from whom scientists can gather genomic data. We are now able to find out more about other archaic humans that bred with early humans. Neanderthals became extinct 30,000 years ago. Their time on earth overlapped with humans and they resembled humans anatomically. The two closely related groups mated and produced fertile offspring, so Neandethal DNA was passed on.

This research is particularly interesting as the Neanderthals were the source for at least a few genetic variations that were adaptive for their human descendants- Their DNA sequences are found in regions of the genome that have been linked to the regulation of skin pigmentation. “We found evidence that Neanderthal skin genes made Europeans and East Asians more evolutionarily fit,” Vernot said, “and that other Neanderthal genes were apparently incompatible with the rest of the modern human genome, and thus did not survive to present day human populations.” The researchers observed that certain chromosomes arms in humans have no Neanderthal DNA sequences, due to mismatches between the two species. For example, they noticed a depletion of Neanderthal DNA in a region that contains a gene for human speech and language.

DOI: 10.1126/science.1245938

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