Genome data point to how Homo sapiens emerged in Africa

Our species emerged in Africa more than 300,000 years ago, with the oldest known Homo sapiens fossils discovered at a site in Morocco called Jebel Irhoud, located between Marrakech and the Atlantic coast.

But the dearth of Homo sapiens fossils from the beginning of our evolutionary history, and the geographic distribution of these remains across Africa, in places like Ethiopia and South Africa, have made it difficult to understand how our species arose and dispersed across the continent before traveling the world. .

A new study exploring genome data from modern African populations offers insight into how this could have happened.

The research indicated that various ancestral groups from across Africa contributed to the emergence of Homo sapiens in a piecemeal fashion, migrating from one region to another and intermingling with one another over hundreds of thousands of years.

The study also concluded that all humans alive today can trace their ancestry back to at least two distinct populations that were present in Africa around a million years ago.

The findings do not support a long-standing hypothesis that a single region in Africa gave rise to Homo sapiens or a scenario involving interbreeding with an unidentified closely related species in the human evolutionary lineage in Africa.

“All humans share a relatively recent common ancestor, but history in the deeper past is more complicated than our species evolving in just a single location or in isolation,” said Aaron Ragsdale, a population geneticist at the University of Wisconsin-Madison, lead author. of the study published this week in the journal Nature.

The ancestral groups were probably scattered across a geographic landscape in a population structure that, according to Ragsdale, “was ‘weak’, meaning that there was continuous or at least recurrent migration between the groups, and this maintained the genetic similarity between the ancestral populations.” ”.

Due to the scarcity of fossil remains and archaeological evidence, researchers have turned to genome data from living people to find clues about the past.

They examined genome data from 290 people, mostly from four geographically and genetically diverse African peoples, to trace the similarities and differences between populations and identify genetic interconnections over hundreds of thousands of years.