The reconstruction of the genetic dynamics that gave rise to modern Homo sapiens is a collaborative effort by archaeologists, paleontologists, and biologists. We know a lot about our ancestors, but there is undoubtedly much more to learn. Modern Homo sapiens are known to be descended from Homo habilis and Homo erectus, among other direct ancestors. The Neanderthals, meanwhile, belonged to a different genetic lineage, so their evolution was parallel. Until recently, we thought the Neanderthals had been extinct for more than forty thousand years, but recent findings suggest that they are still among us. To be exact, they are “in” us.
The science and other stuff to know
A new study published in Scientific Reports shows that the ancestors of modern humans and Neanderthals lived in the same territory—France and northern Spain—simultaneously for at least two millennia. Although the article describing the findings does not mention evidence of genetic crosses between these two lineages, previous research has already provided data from DNA samples that account for genetic interaction.
To obtain information about their movement and activity, the research team co-led by the doctoral student and lead author of the article Igor Djakovic analyzed 28 archaeological samples of human artifacts—bones, blades, arrowheads, or the like—and the same number of artifacts from the Neanderthals, all extracted from the territory circumscribed between what is now the border between France and Spain.
Using a dating technique known as carbon-14 or radiocarbon dating, the team of researchers concluded that Neanderthals in the region became extinct between 40,870 and 40,457 years ago, while modern humans appeared about 42,500 years ago. That leaves a margin of about two thousand years where both species coexisted in presumed harmony and reproduced together.
Archaeological samples prior to the study led by Djakovic had reported genetic crosses between the Neanderthals and the ancestors of Homo sapiens dating back one hundred thousand years. However, the present study suggests that the period of coexistence coincides with a period of “humanization” of the Neanderthals prior to their extinction. That is, the tools they made were beginning to become similar to those of humans.
Djakovic told the French press AFP that “[this period] is associated with substantial transformations in the way people produce material cultures such as tools and ornaments.” These changes, added to the available evidence of genetic crossbreeding, reinforce the hypothesis that the cause of the extinction of the Neanderthals was to have mated with more intelligent and developed humans.
“When you combine that with what we now know, that most people living on Earth have Neanderthal DNA, you could argue that they never really went extinct, in a sense,” Djakovic said. The research concludes by acknowledging its limitations and emphasizing that, despite the triumph of discovering this period of close interaction between our ancestors, “the precise nature of this coexistence remains to be resolved”.