Genetics and the evolution of primate enamel thickness: A baboon model

Leslea J. Hlusko, Gen Suwa, Reiko T. Kono, Michael C. Mahaney

Research output: Contribution to journalArticle

54 Citations (Scopus)

Abstract

The thickness of mammalian tooth enamel plays a prominent role in paleontology because it correlates with diet, and thicker enamel protects against tooth breakage and wear. Hominid evolutionary studies have stressed the importance of this character for over 30 years, from the identification of "Ramapithecus" as an early Miocene hominid, to the recent discovery that the earliest hominids display molar enamel intermediate in thickness between extant chimpanzees and Australopithecus. Enamel thickness remains largely unexplored for nonhominoid primate fossils, though there is significant variation across modern species. Despite the importance of enamel thickness variation to primate evolution, the mechanisms underlying variation in this trait have not yet been elucidated. We report here on the first quantitative genetic analysis of primate enamel thickness, an analysis based on 506 pedigreed baboons from a captive breeding colony. Computed tomography analysis of 44 Papio mandibular molars shows a zone of sufficiently uniform enamel thickness on the lateral surface of the protoconid. With this knowledge, we developed a caliper metric measurement protocol for use on baboon molars worn to within this zone, enabling the collection of a data set large enough for genetic analyses. Quantitative genetic analyses show that a significant portion of the phenotypic variance in enamel thickness is due to the additive effects of genes and is independent of sex and tooth size. Our models predict that enamel thickness could rapidly track dietary adaptive shifts through geological time, thus increasing the potential for homoplasy in this character. These results have implications for analyses of hominoid enamel thickness variation, and provide a foundation from which to explore the evolution of this phenotype in the papionin fossil record.

Original languageEnglish (US)
Pages (from-to)223-233
Number of pages11
JournalAmerican Journal of Physical Anthropology
Volume124
Issue number3
DOIs
StatePublished - Jul 2004
Externally publishedYes

Fingerprint

tooth enamel
Molecular Evolution
Papio
Dental Enamel
Primates
Hominidae
quantitative genetics
Fossils
teeth
fossils
Tooth
Paleontology
additive gene effects
Tooth Wear
calipers
paleontology
enamel
Pan troglodytes
computed tomography
phenotypic variation

Keywords

  • CT analysis
  • Dental variation
  • Enamel thickness
  • Papio hamadryas
  • Primate evolution
  • Quantitative genetics

ASJC Scopus subject areas

  • Agricultural and Biological Sciences (miscellaneous)
  • Anthropology

Cite this

Genetics and the evolution of primate enamel thickness : A baboon model. / Hlusko, Leslea J.; Suwa, Gen; Kono, Reiko T.; Mahaney, Michael C.

In: American Journal of Physical Anthropology, Vol. 124, No. 3, 07.2004, p. 223-233.

Research output: Contribution to journalArticle

Hlusko, Leslea J. ; Suwa, Gen ; Kono, Reiko T. ; Mahaney, Michael C. / Genetics and the evolution of primate enamel thickness : A baboon model. In: American Journal of Physical Anthropology. 2004 ; Vol. 124, No. 3. pp. 223-233.
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