Meeting Abstract
While evolutionary biologists have long appreciated that selection acts only on variation that is heritable, only recently have we had the tools to assess how genetic effects structure morphological variation. Quantitative genetic analyses provide a useful tool for elucidating how genetic effects influence dental variation, yielding testable hypotheses about the genetic modularity and evolutionary history of the dentition. We used a maximum likelihood-based variance decomposition approach implemented in the computer package SOLAR to estimate the heritability of ~70 linear measurements of tooth size for 632 baboons (Papio hamadryas) that are part of a large pedigreed breeding colony housed at the Southwest National Primate Research Center. Because phenotypic correlations can be decomposed into genetic and non-genetic components, as is phenotypic variance for the purposes of heritability estimation, we were able to also estimate genetic correlations between these phenotypes. Our results show that variation in size of the incisors is genetically independent of size variation in the postcanine dentition, and that there is incomplete pleiotropy between premolars and molars. We compared this genetic correlation matrix to phenotypic correlation matrices of dental measurements from other species (Cercopithecus mitis, n=95; Macaca fascicularis, n=98; Papio hamadryas, n=127; Colobus guereza, n=125; Presbytis melalophos, n=83; P. rubicunda, n=80) to test the hypothesis that the genetic modularity estimated for the captive Papio hamadryas population characterizes the dental variation represented by the Cercopithecidae more generally. Implications for the evolution of the Hominidae will be discussed. Supported by NSF grants BCS 0616308, 0500179, 0130277, and NIH P51 OD011133 which supports the SNPRC.
