Genetics has become a good ally of the main events in history, but not only the most recent, but the oldest. Now, a team of researchers has managed to "genetically track" the migrations that modern humans carried out from Africa thousands of years ago.
Only 10% of genetic mutations that occur randomly in a population as a consequence of reproduction have an adaptive value, that is, they favor the survival of the individual who suffers from it and, therefore, are naturally selected. Recall the case of very low lactose intolerance in populations that were early livestock producers or hemoglobin production in the Tibetan population that allowed it to survive high altitudes.
Most mutations, however, do not provide an advantage to the organism that suffers from them and its transmission to the following generations is explained by other reasons: the non-adaptive differences between humans (skin color, facial features, blood group ...) are the product of random genetic changes of direction that result from the division of a tribe into smaller groups that leave the tribe to migrate to another area and settle separately.
Specifically, the team of researchers, led by scientists from the University of Washington (USA), has analyzed variations in the number of copies of the genome (segments of the genome that are repeated or deleted throughout history) of 236 individuals of 125 populations distributed throughout the world.
He then compared them to data from Neanderthals and Denisovans (Homo whose finding was announced in 2010 and found in Siberia).
In total, this work identifies 14,467 variations in the number of copies in the genomes, but not all of them are present in all populations, Irene Gallego Romero, from the University of Chicago and one of the signatories of this article, told Efe by telephone.