A good part of the world’s population shares a significant Neanderthal heritage in their genes. If we exclude people of African ancestry, between 1% and 2% of people’s DNA originates from the otherwise extinct species. And the Neanderthals (Homo neanderthalensis) constitute the human species closest to ours, not only in biological terms, but also in coexistence.

47,000 years ago somewhere in Eurasia. A new study has revealed new details about the period in which our species (H sapiens) and they lived together and procreated. The new study tells us that the encounter between species was not a singular event but the result of either prolonged contact or a series of intermittent contacts over millennia.

The study offers an update to the “timeline” of relationships between the two species. The first encounters between the species would have started about 50,500 years ago and would have lasted for about seven millennia.

The new timeline. The new estimate is consistent with archaeological evidence that indicates that Sapiens and Neanderthals lived together for a long period (between 6,000 and 7,000 years) in some areas of Eurasia. Previous estimates of the timeline of the encounters estimated that these were somewhat more recent, as they would have occurred between 54,000 and 41,000 years ago, the team continues to explain.

“Timing is really important because it has direct implications on our understanding of the era of migration out of Africa, since most non-Africans inherit between 1% and 2% of their ancestry from Neanderthals,” indicated in a press release Priya Moorjani, co-author of the study.

59 + 275. For the study, the team analyzed more than 200 samples, 59 of them belonging to prehistoric human remains and 275 belonging to modern humans. The analysis not only allowed us to date the period of coexistence more precisely but also to investigate the evolutionary mechanisms that led these genes to reach our days.

The key to this is in the “genomic deserts”, regions of the sapiens DNA in which Neanderthal genes are never present, possibly because these genes would not be compatible with the life of our species, resulting in the death of the individuals who died. They will inherit them. They thus observed that in ancient humans, Neanderthal DNA began to group together in some areas, which precisely left evidence of these evolutionary mechanisms at work.

Details of the analysis were published in an article in the magazine Science.

More than just code. The study has also served to delve deeper into the functions of the genes inherited from our taxonomic “cousins.” According to the team, these genes are usually linked to the immune system, skin pigmentation and metabolism, something that previous studies had already reported. They also remember that these genes, for example, could have been helping our species fight Covid.

A second study. The study has been published practically at the same time as a second work, it’s in the magazine Naturein which the process of genetic analysis of human remains from the same period was reported. This is the oldest study ever carried out using human remains and its results help corroborate the results of the analysis published in Science.

Image | Max Planck Institute for Evolutionary Anthropology with DALL-E & BioRender