(ORDO NEWS) — Analysis of genomic data and archaeological records has added to the picture of how Europe and Asia were settled by Homo sapiens who came from Africa.
Scientists have found evidence of several migratory waves in different directions, during which the ancestors of modern East Asian people first settled Western Europe and then were displaced by another population.
Anatomically modern humans left Africa several times, starting at 215,000 years ago and ending with more recent migrations between 70,000 and 60,000 years ago.
The prevailing opinion is that about 45,000 to 40,000 years ago this wave of movement from Africa dispersed in some region between Africa and Europe, giving rise to those populations that we now call European and East Asian.
But that picture has been complicated by the recent discovery in Bacho Kiro, Bulgaria of 45,000-year-old human remains that are genetically closer to an ancient East Asian population than to a European one. This suggests that the two branches were not clearly separated, migrating to different places at the same time.
In a study published in the journal Genome Biology and Evolution, scientists from the Universities of Padova and Bologna looked for a plausible explanation for these population dynamics.
“Genetics teamed up with archaeologists in one joint study, rather than working in different groups with their own work,” said study author Luca Pagani of the University of Padova.
“An interdisciplinary approach to such complex biocultural events is incredibly valuable.” Computational and statistical methods are widely used to reconstruct a variety of family trees that can match the available genetic data.
In this case, the scientists used material evidence from Paleolithic populations in Europe as an additional criterion for choosing between family trees that were equally consistent with the genetic data.
“Of several possible pedigree models that could accommodate the genetic data, we chose one that fit the data well,” says first author Leonardo Vallini of the University of Padova.
According to the findings, instead of a clear geographical bifurcation between East and West, there were several waves of migration.
During the first, which occurred about 45,000 years ago, the populations that later came to dominate East Asia colonized Europe and met the Neanderthals, with whom they interbred before moving on to the East.
This explains the presence in Bacho Kiro of individuals with genomes related to the genomes of modern East Asian populations.
In the subsequent wave, populations closer to modern Europeans colonized Europe, breeding with previous local populations that still retained the genetic traces of the Neanderthals and the “East Asian” wave. This may also explain the sudden emergence of new stone working techniques that were not yet common in Western Europe.
According to Marco Peresani, an anthropologist at the University of Ferrara who was not involved in the study, “Despite the difficulty in attributing genetic samples to Paleolithic cultures, the conclusion proposed by the study is indeed interesting.”
The authors hope that future studies using paleoclimatological data and genomic samples from the Indian subcontinent will further elucidate the sequence of migratory waves into Eurasia.
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