A significant genetic characteristic was discovered to have originated from Neanderthals, as revealed in research spearheaded by academics at University College London.
El Sidron Neanderthals taste wild mushrooms, pine nuts and forest moss. Image credit: Abel Grau, CSIC Communication.
“Dental morphology offers profound insights into human evolutionary history, with meticulously preserved ancient dentition serving as crucial artifacts for archaeologists, illuminating pivotal transitions such as the adoption of cooked foods and the subsequent reduction in human tooth dimensions,” commented Dr. Kaustubh Adhikari, a research fellow at University College London.
“However, the genetic underpinnings of variations in tooth size and form within contemporary human populations remain largely obscure, partly due to the inherent difficulties in accurately quantifying dental structures.”
“Our investigation has successfully pinpointed a multitude of genes that exert influence over dental development, with certain genes accounting for disparities observed among different ethnic demographics.”
For the purposes of this study, Dr. Adhikari and his research team analyzed data sourced from 882 voluntary participants residing in Colombia, who represented a diverse admixture of European, Indigenous American, and African ancestries.
The collected dataset encompassed measurements of dental crowns – specifically, the dimensions of the tooth portion visible above the gingival line – which were meticulously acquired from three-dimensional renderings of dental cast impressions.
Subsequent to this, the researchers correlated these dental measurements with the participants’ genotypic profiles through a comprehensive genome-wide association study. This was achieved by employing a sophisticated analytical methodology known as multiomics, which integrates information from a multitude of distinct data sources.
Through this rigorous analysis, the study identified 18 distinct genomic regions implicated in modulating the size and configuration of various tooth types, with a remarkable 17 of these regions not having been previously associated with dental dimensions.
Among the newly identified associations was a gene believed to have been introduced into the human genome through interbreeding with ancient Homo sapiens populations, indicating Neanderthal ancestry.
This specific genetic marker, which plays a role in the biological pathways governing tooth formation, was exclusively identified in individuals of European lineage. Furthermore, those carrying this variant exhibited thinner incisors; the thickness of these anterior teeth, located at the front of the oral cavity, was assessed from posterior to anterior aspects.
Generally speaking, individuals of European descent tended to possess smaller teeth.
The scientific inquiry also uncovered associations related to tooth dimensions involving a gene already recognized for its impact on incisor morphology in East Asian populations. This study further demonstrated that this gene, identified as EDAR, also dictates the overall breadth of all teeth.
“A subset of the genes contributing to the typical variability in dental dimensions among healthy individuals can also be implicated in pathological variations, such as the absence of tooth development or other compromised oral health conditions,” stated Dr. Qing Li, a researcher affiliated with Fudan University.
“We hold an optimistic outlook that our findings could translate into valuable clinical applications, potentially enabling genetic screening for individuals presenting with specific dental afflictions to aid in diagnosis, or even paving the way for gene therapy-based treatments for certain dental anomalies in the future.”
“Our research did not elucidate whether the genes dictating tooth shape were subjected to selective evolutionary pressures due to particular advantages conferred to dental health. Consequently, it remains conceivable that these genes might have been favored for their influence in other biological domains, with divergences in tooth morphology arising as a secondary consequence,” remarked Professor Andrés Ruiz-Linares, an academic affiliated with University College London, Fudan University, and Aix-Marseille University.
A scientific publication detailing these discoveries was disseminated on December 12th in the esteemed 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
