The first genetic variations that make us humans appeared more than 100,000 years ago

New research from Spain has identified the first two moments in history when different genetic variants would have made the human species unique: one occurred around 40,000 years ago, associated with the growth of the Homo sapiens population and its departure from Africa. The other, older, took place more than 100,000 years ago, linked to the time of greatest diversity of Homo sapiens types on the present-day African continent.

An international study conducted by the University of Barcelona highlights some critical moments in the human evolution at the genetic level: scientists have estimated certain periods in which some of the genetic variants that characterize our species emerged and were concentrated to a greater extent, distinguishing the current human being from other species of Homo.

In the new study, led by Cedric Boeckx and published in the journal Scientific Reports, researchers compared species-specific variants of Homo over time, finding out how these genetic variants and modifications they were accumulated in several periods. These variants they reflect, for example, critical events like the point of separation between Homo sapiens and other human species around 100,000 years ago.

Two crucial moments

In this framework, the results show that there were two crucial moments in which the concentration of different genetic variants marked human evolution with fire and shaped the characteristics that define the human being today. Concretely, this makes 40,000 years when the growth of the population of Homo sapiens and its departure from Africa took place, and more than 100,000 years oldwhen the greatest diversity of Homo sapiens types was recorded in this same area of ​​the planet.

According to a Press releasethe specialists analyzed the genetic variants linked to the brain, given that the development of this organ was the main driving force behind the changes and behaviors associated with the evolution of Homo sapiens, marking the moment of its “take-off” from other Homo species. For example, they studied genetic changes that other research associates with changes in the volume of the cerebellum, corpus callosum, and other brain structures that characterize modern humans.

In this way, they discovered that brain tissue shows gene expression profiles (referring to the impact of genes on body functions) particular and specific to different times in human history. In other words, they identified how and when certain genes involved in neuronal development were expressed more. This allowed them to date the two critical genetic moments that would have determined the separation of Homo sapiens from the evolution of other human species.

Comparison of the skulls of different primitive species of Homo. Credits: Chris Stringer, Natural History Museum, UK / Wikimedia Commons.

mosaic evolution

At the same time, they also identified the predominance of genetic variants over behavior and facial structure, other vital conditions in the differentiation of our species. In this sense, they discovered sets of genetic variants that affect the evolution of the face and that would have been concentrated between 300,000 and 500,000 years ago, a period close to the dating of the first fossils of Homo sapiens discovered in Morocco.

From these genetic studies, scientists conclude that all these data serve to prove once again that There were none evolution linear of the human speciesbut rather that the human being has undergone a mosaic evolution: the variants of hominids, each with its specific level of development, have coexisted and been linked at different times in history.


Temporal mapping of high-frequency derived genetic variants supports the mosaic nature of Homo sapiens evolution. Alejandro Andirko et al. Scientific Reports (2022). OF THEM:

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