The 84th Annual Meeting of the American Association of Physical Anthropologists (2015)


The integration of genetic and phenotypic data to better understand human and non-human primate limb morphology

BRANNON I. HULSEY1, BENJAMIN M. AUERBACH1, LORENA M. HAVILL2, CHARLES C. ROSEMAN3 and GRACIELA S. CABANA1.

1Department of Anthropology, University of Tennessee at Knoxville, 2Department of Genetics, Texas Biomedical Research Institute, 3Department of Anthropology, University of Illinois at Urbana-Champaign

March 26, 2015 , Gateway Ballroom 2 Add to calendar

Variation in human limb morphology results from complex interplay involving genetics, biomechanics, nutrition, and climate. Multiple studies show ecogeographic and clinal patterns in limb lengths and proportions and the action of evolutionary forces. The ways in which evolutionary processes shape these patterns are not well understood. The study presented here merges genotype and phenotype to investigate the genetic influences on morphology that may allow the evolution of human limb lengths and proportions.

Phenotypic and genetic variance, evolvability, and morphological integration between limb segments were examined in four large pedigreed samples (tamarins, two samples of baboons, and humans). Non-human primates serve as models for humans and allow for characterization of patterns of covariation among traits across related taxa. Results show variation in the relationship between limb segments across taxa. All species show higher covariance between homologous distal versus proximal limb segments. Humans show higher levels of evolvability and lower levels of integration relative to the other taxa, indicating that some aspects of limb morphology are stable across taxa, while humans are distinct in other aspects. Genotype data available for one baboon sample allowed for estimates of heritability (0.68 to 0.917, p < 1.1*10-9) and identification of one significant and several suggestive quantitative trait loci (QTLs) – regions of the genome likely to harbor genes that influence variation in specific aspects of limb morphology. The results of these analyses are applied to develop a model of the processes that shape human limb length and proportion variation.