Researchers discover which dental traits reveal genetic relationships
TÜBINGEN, Germany: Given that teeth are often the best-preserved part of human skeletons, researchers across many disciplines frequently rely on them to reconstruct genetic affinities among ancient populations. A pair of researchers have now discovered which dental features are most likely to indicate genetic relationships and which features are more likely to reflect environmental adaptations or natural selection.
The researchers—Drs Hannes Rathmann and Hugo Reyes-Centeno—are both from the Deutsche Forschungsgemeinschaft Center for Advanced Studies “Words, Bones, Genes, Tools: Tracking Linguistic, Cultural and Biological Trajectories of the Human Past” at the University of Tübingen in Germany, and investigated which dental traits, or combinations of traits, are better at preserving neutral genetic signals. Though it has been well established in the existing literature that tooth form is highly heritable and selectively neutral, it has been less clear which traits best display genetic legacies.
By examining 27 common dental traits and more than 134 million possible trait combinations, the researchers were able to demonstrate that certain traits, such as the mesial ridge and protostylid, possessed a higher utility for inferring genetic relationships between populations. The findings could be helpful across a range of different contexts, according to Rathmann.
“We anticipate that our findings will impact future research in forensic sciences, archaeology and palaeoanthropology because, in these academic fields, dental remains are widely used as a biogeographic ‘fingerprint’ of deceased individuals when DNA is not preserved,” he told Dental Tribune International.
“We propose that future studies should prioritise the top-performing dental traits and trait combinations found in our study, as they allow for more accurate inferences about neutral genetic affinities,” Rathmann continued.
The researchers have several further studies in progress that are related to this work, Reyes-Centeno added.
“We will be reassessing studies that have drawn inferences on ancient human relationships and migrations using dental traits that we now know might not have been very useful,” he said.
“We are also planning to collect data on a smaller regional scale from individuals from populations that were not represented in our published study. It is important to look at diverse populations around the world in order to further refine our conclusions,” explained Reyes-Centeno.
The study, titled “Testing the utility of dental morphological trait combinations for inferring human neutral genetic variation”, was published online on 6 May 2020 in the Proceedings of the National Academy of Sciences of the United States of America, ahead of inclusion in an issue.