The first sequencing of the Y chromosome genes of Neanderthals revealed absolute differences with mismocromosoma modern human, which would explain why both species were kept separate, according to a study published Thursday in the United States.
scientists have known since 2010 that the populations of Eurasian origin are between 2.5 and 4% of genes inherited from Neanderthals, as a result of crosses between the two species 50,000 years ago, shortly after the modern humans reached Eurasia from Africa.
humans and Neanderthals coexisted until the extinction of the latter, approximately 30,000 years ago.
the Y chromosome, which brings masculine traits , was the last major component of the Neanderthal genome was analyzed, require researchers, whose work was published in the journal “American journal of Human Genetics”.
All previous studies had focused on the sequencing of DNA from Neanderthal fossils or mitochondrial DNA passed on by mothers to children of both sexes.
“the characterization of the Y chromosome Neanderthal helps us better understand the differences between populations that led the Neanderthals and modern humans, “said Fernando Mendez, a researcher at Stanford University in California, one of the main authors.
This sequencing also provides new information about the relationship between Neanderthals and modern humans, and certain genetic factors that could separate the two species.
Their analysis suggests that Neanderthals and humans diverged about 590,000 years ago, which fits with previous findings.
the geneticists suggest that the Y chromosome neandertal is completely different from any other Y chromosome from modern human analyzed, which suggests that this genetic line died.
they also found some strange differences in the codes genetic proteins between the Y chromosomes of Neanderthals and humans. Three of these differences are known genes in humans that cause specific incompatibilities in males mutations.
So, some antigens derived from one of these three genes are apparently responsible for an immune response in women pregnant attacking their fetuses, causing abortions.
researchers believe that some of these incompatible on the Y chromosome Neanderthal genes may have played a role in maintaining a separation between ancient humans and Neanderthals discouraging crossings.
However, it considers that further studies are needed to confirm this finding. The Y chromosome genes represent between 1.5 and 2% of the total DNA in cells.
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