The Near East is believed to be where much of the interbreeding between humans and Neandertals took place.

There are traces of Neandertal in the genomes of modern humans. New insights were offered in the exploratory study.

Steven Churchill is a professor of evolutionary anthropology at Duke University.

We often think of evolution as a branch on a tree, and researchers have spent a lot of time trying to trace back the path that led to us. We now know that it isn't a tree, but a series of streams that converge and differ at different points.

Ann Ross is a professor of biology at North Carolina State University.

The picture is not easy to understand. There was interbreeding. Because Neandertals lived in what is now Europe, modern Asian populations have more Neandertal genes than modern European populations.

It has been suggested that Neandertals interbred with modern humans before they spread to Asia. We wanted to see what additional light we could shed on this by looking at the facial structures of prehistoric humans and Neandertals.

Ross says that they can trace how populations moved over time. Evidence shows that the Near East was an important crossroads in the evolution of humans.

The researchers collected data from the literature. The data set included 13 Neandertals, 233 Homo sapiens, and 83 modern humans.

The researchers looked at the size and shape of key facial structures with the help of standard craniofacial measurement. The researchers were able to do an in-depth analysis to determine if a given human population was likely to have interbred with Neandertal populations.

The Neanderthals had large faces. There is no genetic link between humans and Neandertal populations. We did a more robust analysis of the facial structures.

To determine the likelihood that Neandertal and human populations were connected, the researchers accounted for environmental variables that are associated with changes in human facial characteristics.

Ross says that the facial characteristics they focused on were not influenced by the climate. The influence of Neandertal interbreeding in human populations was tracked using facial shape. Humans were smaller than Neandertals. After they had bred with Neandertals, the size of human faces decreased. There was evidence of interbreeding with Neandertals.

The study was an exploratory one. We don't have as much data on facial structures as we would have liked, so I wasn't sure if this approach would work. The results are compelling.

The Natufians, who lived more than 11,000 years ago on the Mediterranean in what is now Israel, Jordan, and Syria, would be included in the measurement.

NC State is located in the state of North Carolina.