One of these genetic variants was inherited from Neanderthals, according to a study led by University College London researchers.
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El Sidron Neanderthals taste wild mushrooms, pine nuts and forest moss. Image credit: Abel Grau, CSIC Communication.
“Teeth can tell us a great deal about human evolution, as well-preserved ancient teeth are particularly important to archaeologists, shedding light on milestones such as when we transitioned to cooked food and human tooth sizes began to shrink,” said Dr. Kaustubh Adhikari, a researcher at University College London.
“But little is known about the genetic basis of variation within the modern human population on tooth size and shape, partly due to challenges in measuring teeth.”
“We have now identified numerous genes that impact the development of our teeth, some of which are responsible for differences between ethnic groups.”
For the study, Dr. Adhikari and colleagues used data from 882 volunteers in Colombia, of mixed European, Native American and African ancestry.
The dataset included dental crown measurements — dimensions of the part of the tooth visible above the gums — derived from 3D scans of dental plaster casts.
The researchers compared these measurements with the participants’ genetic information in a genome-wide association study, using an analysis approach called multiomics that brings together numerous data sources.
They identified 18 genome regions that influence the size and shape of different groups of teeth, 17 of which had not been previously linked to tooth dimensions.
One of the novel associations was on a gene believed to be inherited from Neanderthals due to interbreeding with ancient Homo sapiens.
This genetic variant, which contributes to the biological pathway of tooth development, was only found in those of European descent, and carriers of the variant have thinner incisors (thickness of the incisors, the eight teeth situated at the front of the mouth, was measured from back to front).
On the whole, those of European descent had smaller teeth.
The scientists also found associations with tooth dimensions on a gene that was already known to impact incisor shape in East Asian people, while the new study found that the gene, called EDAR, also determined the width of all teeth.
“Some of the genes that contribute to the normal variation of tooth dimensions among healthy people can also contribute to pathogenic variation, such as teeth failing to grow in or other dental health conditions,” said Dr. Qing Li, a researcher at Fudan University.
“We hope that our findings could be useful medically, if people with particular dental problems could undergo genetic tests to help in diagnosis, or if some dental anomalies could be treated one day with gene therapies.”
“Our findings did not shed light on whether the genes that identify tooth shape were selected in evolution due to particular advantages to dental health, so it’s possible that the genes may have been selected due to the influences they have in other areas, with tooth shape differences resulting as a side effect,” said Professor Andrés Ruiz-Linares, a researcher at University College London, Fudan University and Aix-Marseille University.
A paper on the findings was published December 12 in the journal Current Biology.
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Qing Li et al. PITX2 expression and Neanderthal introgression in HS3ST3A1 contribute to variation in tooth dimensions in modern humans. Current Biology, published online December 12, 2024; doi: 10.1016/j.cub.2024.11.027
