According to a paper published in the latest issue of biology, American anthropologists' study of ancient skulls shows that most of the Neanderthal and human hybrids occurred in the "Near East" region between North Africa and Iraq around 50,000 years ago. Experts came to their conclusions after analyzing the facial structure of the prehistoric skulls of 13 Neanderthals, 233 prehistoric Homo sapiens, and 83 modern humans.
Skull samples used for analysis were reportedly found in different locations in Asia, Europe and Africa. The aim was to look for signs of Neanderthal influence on the anatomy of the human face, the result of the so-called "hybrid hybrids".
Steven Churchill, a co-author of the study and professor of evolutionary anthropology at Duke University in the United States, said that Neanderthal faces are large, but size alone does not establish any genetic connection between human and Neanderthal groups.
The research team's work involved a more robust analysis of facial structures. Some ancient skulls do show such evidence of Neanderthal influence on human facial anatomy, leading researchers to identify the Near East as the area where most hybridizations occurred.
Professor Churchill said this sharing of genetic material should have occurred between 50,000 and 40,000 years ago, when paleolithic modern humans lived in the same period and in the same region as Neanderthals.
Changes in facial shape and development can reflect changes in genetic makeup, both of which occurred after early modern and Neanderthal hybridization.
The researchers found that changes in facial shape and development can reflect changes in genetic makeup, both of which occurred after early modern and Neanderthal hybridization.
The scientists compared measurements taken from similar facial structural features to see if there were clear signs of hybridization in the ancient skulls they analyzed.
Other factors that may have contributed to the change were also taken into account to ensure that any features found had a clear link to Paleolithic hybridization.
Professor Churchill said it was strange that modern Asian populations seemed to have more Neanderthal DNA than modern European populations because Neanderthals lived in what is now Europe. This suggests that when the prehistoric ancestors of modern humans left Africa, they mated with Neanderthals in the Near East before migrating to Asia.
Ann Ross, the study's corresponding author and a professor of biological sciences at North Carolina State University, said that by assessing facial morphology, we can track how people move and interact over time. And this evidence shows us that the Near East is an important crossroads, both geographically and in the context of human evolution.
She said the shape of the face is a more useful variable to track the effects of Neanderthal hybridization in human populations over time, and the results the research team got were really compelling.
To build on this, the team hopes to incorporate measurements from more human groups, such as the Natuffians, who lived more than 11,000 years ago in what is now Israel, Jordan and Syria.
Text/Nandu reporter Chen Lin