Abstracts (first author)
Quantitative genetic variation, selection and secular change of skull shape in humans
The combined use of geometric morphometrics and quantitative genetics provides a set of powerful tools for obtaining quantitative information that is crucial for many important questions concerning the evolution of shape. In particular, the demographic information that is available for human populations make humans a unique study system for studying the mechanisms of evolutionary change in morphological traits. We investigate skull shape in the population of Hallstatt (Austria), where a collection of human skulls with associated records offer a unique opportunity for such studies. We use an individual-based statistical model to estimate the genetic covariance matrix, and characterize selection using fitness estimates from demographic data. We find clear evidence for directional selection, but not for nonlinear selection (stabilizing or disruptive selection). The predicted response to this selection, computed with genetic parameters from the population, does not match the estimate of secular change over the 150-year range of the data. We discuss possible reasons for the mismatch.