Max Planck Research Group
Evolution of Polygenic Traits 
 

Populations live in constantly changing environments, but how do they adapt after a sudden environmental change? Most complex traits are polygenic under stabilizing selection, where the population mean is stabilized at an average trait value, i.e. the optimum. Theoretical studies suggest that the adaptation of these traits to a sudden shift in their optima occurs through small changes in the frequency of many alleles, i.e. polygenic adaptation. Many factors, such as population size, selection pressure, pleiotropy and genetic redundancy among contributing loci, affect polygenic adaptation. While theoretical models of adaptation make predictions about the phenotypic and genomic changes of evolving populations, empirical studies to test these predictions are scarce.

In our group, we study the genetic basis of polygenic adaptation in complex traits, and the role of factors such as population size, selection, redundancy and pleiotropy on adaptation. We take a multidisciplinary approach, integrating temporal genomic and high-throughput phenotypic data from experimental evolution in highly replicated Drosophila populations with theoretical models and computer simulations. The complex traits we study range from physiological traits such as adaptation to diet, temperature and developmental time, to morphological traits such as body and egg size. Identifying the loci underlying adaptation provides insight into the adaptive potential of populations and the repeatability of adaptation between different populations and species.