Statistical genetics of molar cusp patterning in pedigreed baboons: Implications for primate dental development and evolution

Leslea J. Hlusko, Mary Louise Maas, Michael C. Mahaney

Research output: Contribution to journalArticlepeer-review

39 Scopus citations


Gene expression and knock-out studies provide considerable information about the genetic mechanisms required for tooth organogenesis. Quantitative genetic studies of normal phenotypic variation are complementary to these developmental studies and may help elucidate the genes and mechanisms that contribute to the normal population-level phenotypic variation upon which selection acts. Here we present the first quantitative genetic analysis of molar cusp positioning in mammals. We analyzed quantitative measures of molar cusp position in a captive pedigreed baboon breeding colony housed at the Southwest National Primate Research Center in San Antonio, Texas. Our results reveal complete pleiotropy between antimeric pairs of traits - i.e., they are influenced by the same gene or suite of genes. Mandibular morphological homologues in the molar series also exhibit complete pleiotropy. In contrast, morphological homologues in maxillary molar series appear to be influenced by partial, incomplete pleiotropic effects. Variation in the mandibular mesial and distal molar loph orientation on the same molar crown is estimated to be genetically independent, whereas the maxillary molar mesial and distal loph orientation is estimated to have partially overlapping genetic affects. The differences between the maxillary and mandibular molar patterning, and the degree of genetic independence found between lophs on the same molar crown, may be indicative of previously unrecognized levels of modularity in the primate dentition.

Original languageEnglish (US)
Pages (from-to)268-283
Number of pages16
JournalJournal of Experimental Zoology Part B: Molecular and Developmental Evolution
Issue number3
StatePublished - May 15 2004
Externally publishedYes

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Molecular Medicine
  • Animal Science and Zoology
  • Genetics
  • Developmental Biology


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