There is a new chronology about the love relationships between Homo sapiens and Neanderthals

Modern humans are the result of genetic mixing between hominid lineages. One of the most famous anthropological meetings is the one held by Homo sapiens and his cousin, Homo neanderthalensis (Neanderthal). The time frame in which both species coexisted becomes more precise as genomic science evolves. Two recent independent investigations have managed to determine with never-before-seen precision the moment of miscegenation.

The studies included genomes of modern humans from Europe and Asia, who record the highest proportion of genes inherited from Neanderthals. They also analyzed 59 ancient genomes, sampled between 45,000 and 2,200 years ago. With the information, the researchers were able to estimate an average date on which the interbreeding event occurred and how long it lasted. The independent reports, published in Science and Natureindicate that Homo sapiens and Neanderthals had offspring 47,000 years ago. Until now, the best estimates were only able to specify that interbreeding would have occurred in a time window that went back between 54,000 and 41,000 years.

“Although ancient genomes were published in previous studies, they had not been analyzed to look at Neanderthal ancestry in this detailed way. We created a catalog of segments of Neanderthal ancestry in modern humans. By jointly analyzing all these samples together, we inferred that the period of gene flow was around 7,000 years,” said Manjusha Chintalapati, study co-author of Science. The gene flow between the two lineages is much greater than expected.

A map in the genes of the human being’s routes

Precision about the interbreeding event is essential to understand the migration of the Homo sapiens. This originated in Africa, while the Neanderthal is native to Eurasia. A momentous lineage mixing event involves determining the exact moment when the direct ancestor of modern humans reached other continents and settled there long enough to become familiar with the region’s inhabitants.

“The new dates also imply that the initial migration of modern humans from Africa to Eurasia was basically more than 43,500 years ago,” explains the University of Berkeley, California, in a statement. The genetic approach is consistent with the available archaeological evidence. Both approaches offer a more precise overview of the migratory movements of the ancestors of contemporary humans.

Currently, non-African humans have between 1 and 2% Neanderthal ancestry. For the authors of the recent study, time and close coexistence between hominids can explain why people who live in East Asia have 20% more Neanderthal genes than those who live in Western Asia and Europe. When humans arrived in those regions 47 thousand years ago, they would have already had those Neanderthal genes.

Neanderthal genes that have survived within Homo sapiens modern are related to immune functions, skin pigmentation and metabolism. Since Eurasian hominids were adapted to cold climates compared to those that came from Africa, it is estimated that gene flow allowed Homo sapiens better cope with the new environment and thrive in it. It is likely that the same phenomenon occurred with the Denisovans, another lineage of hominids that lived in the high mountains.