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Genetic correlations between mandibular molar cusp areas in baboons
Leslea J Hlusko1, Nicholas Do, Michael C Mahaney
1Department of Integrative Biology, University of California at Berkeley, Berkeley, CA 94708, USA. hlusko@berkeley.edu
American Journal of Physical Anthropology
|December 13, 2006
Summary
Baboon molar cusp size variation is heritable and sexually dimorphic, indicating a significant genetic basis. These findings in Papio hamadryas challenge simple developmental models for primate dental evolution.
Area of Science:
- Evolutionary Biology
- Primatology
- Quantitative Genetics
- Dental Morphology
Background:
- Dental variation is crucial for understanding primate evolution, influencing environmental interactions and social behaviors.
- Previous studies on cusp size variation primarily focused on hominoids, leaving gaps in knowledge for other primate taxa like baboons.
- The genetic underpinnings of dental variation, particularly cusp size, remain incompletely understood across many primate lineages.
Purpose of the Study:
- To investigate the heritability and genetic basis of two-dimensional (2-D) mandibular molar cusp size variation in baboons (Papio hamadryas).
- To determine if cusp size variation is sexually dimorphic.
- To analyze genetic correlations between different cusps on the same molar and along the tooth row.
Main Methods:
- Quantitative genetic analyses were performed on a captive, pedigreed baboon population (Papio hamadryas).
- Measurements of 2-D mandibular molar cusp size were collected.
- Genetic correlations between cusp areas and crown width were statistically assessed.
Main Results:
- Molar cusp size variation in baboons is significantly heritable and exhibits sexual dimorphism.
- High genetic correlations (estimated at one) were found between specific cusp pairs on the first molar (e.g., metaconid-hypoconid, entoconid-hypoconid).
- Lower genetic correlations were observed in second and third molars, with some cusp pairs showing no significant genetic correlation, deviating from expected developmental patterns.
Conclusions:
- Genetic factors play a substantial role in shaping mandibular molar cusp size variation in baboons.
- The observed patterns of genetic correlations suggest complex developmental or genetic influences on molar morphology.
- Further research is needed to elucidate the developmental and genetic mechanisms underlying these observed dental variations in primates.
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