It is a well known fact that many modern humans carry in their genetic code up to 4% of the DNA of Neanderthals.
But an international study, led by School of Medicine, Stanford University USA, has just revealed that the Y chromosome, the genetic neandertal package passed from parents to children-is not present in modern populations.
“We found chromosome And Neanderthals in any of the samples analyzed, “said Peruvian scientist Carlos Bustamante, co-author of the research.
” that does not prove that the chromosome has been completely extinguished, but it probably is, “added Bustamante.
the study was published in American Journal of Human Genetics (American Journal of Human Genetics).
Our ancestors and Neanderthals interbred approximately makes about 50,000 years after the Homo sapiens left his native Africa and began to colonize Eurasia.
and there is still a small amount of DNA in our genes that is the legacy of that miscegenation.
Photo: Getty
But the new analysis reveals that the Y chromosome Neanderthal is completely different from that of modern humans.
the researchers say it is possible that chromosome initially circulated in the genetic code of modern humans, but lost, random, over the millennia.
Another possibility is that genes that chromosome were incompatible with other genes of Homo sapiens .
And, in fact, scientists found evidence supporting the latter theory.
Some of the Y chromosome genes of Neanderthals are part of the immune system.
Three of them are “minor histocompatibility antigens,” or genes HY, which resemble those that transplant surgeons checked to ensure that donors and organ recipients have immune profiles similar.
in addition, these genes of Neanderthals found on the Y chromosome are specific men.
in theory, the immune system of women can attack a male fetus that has some of these Neanderthal genes.
And if miscarriages of babies bearing these chromosomes are produced consistently, that would explain its absence in the genetic code of modern humans.
so far they are only hypotheses, but it is known that the immune system of women today day may react negatively to the male offspring if there is genetic incompatibility.
“the functional nature of the mutations that we found suggests that sequences the Y chromosome Neanderthals may have played a role in mating ancient humans and Neanderthals “expicó Bustamante.
” we need to do more experiments to prove it and we are working on it, “added the scientist.
But, for now, the mystery will remain unsolved .
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