Ancient Skull Research Provides New Information on Human-Neanderthal Cross-Breeding

The Near East was a cross roads for admixture

It is generally accepted that interbreeding has left traces of Neanderthal DNA in the genome of modern people. In a recent Biology

¹

article, the facial structure of archaic skulls were evaluated and revealed evidence in favor of the theory that much of this interbreeding occurred in the Near East. The published literature was used by the researchers to gather information on craniofacial morphology for this investigation. In the end, this produced a data set that contained 83 modern humans, 233 ancient Homo sapiens, and 13 Neanderthals.

The size and shape of important facial components were evaluated by the researchers using reliable standard craniofacial measurements. The researchers were therefore able to conduct a thorough investigation to establish the likelihood that a specific human population interbred with Neanderthal populations as well as the degree of that probable interbreeding. To assess the possibility that the relationships they found between Neanderthal and human populations were the consequence of interbreeding rather than other causes, the researchers also took into account environmental factors that are linked to changes in human face traits.

A plot of CVA canonical axis 2 (CAN 2) on axis 1 (CAN 1) represents 80% of the total variation. Neandertals cluster together (narrow orbits, wide nasal breadth, and large geometric mean); Near Eastern Middle Paleolithic AMH fall in between the Neandertal and the other AMH samples. The Near Eastern/North African AMH sample has intermediate orbit and nasal breadths, and a small geometric mean and is closest to the recent East African sample.

The authors concluded climate had little of an impact on the facial features they concentrated on. Instead, genetic factors were more likely the culprit. The impact of Neanderthal interbreeding on human populations over time was also discovered to be better tracked using facial form as a variable.

Simply put, Neanderthals were larger than humans. After humans bred with Neanderthals for several generations, the faces of Neanderthals gradually shrunk in size. However, several face characteristics still showed signs of interbreeding with Neanderthals in terms of their physical morphology. Facial morphology analysis allows us to follow the movements and interactions of populations over time. The Near East was a significant crossroads both geographically and in terms of human evolution, the evidence demonstrates.

There was interbreeding, as is known.

Although Neandertals lived in what is now Europe, it is odd that present Asian populations appear to have more Neandertal DNA than modern European populations. It has been hypothesized that Neandertals interbred with modern humans as they departed Africa but before expanding to Asia.

1. Churchill, S. E., Keys, K., & Ross, A. H. (2022). Midfacial morphology and Neandertal–modern human interbreeding. Biology, 11(8), 1163. https://doi.org/10.3390/biology11081163