Evolutionary dynamics of small versus large-size populations: the interaction of genetic drift with natural selection


Natural selection and genetic drift are two major forces that can drive evolutionary change. It is well-known that population size is very relevant for both mechanisms. Nevertheless, little is known about how much genetic drift interacts with natural selection as a function of population size, previous evolutionary history, or ongoing selection. To tackle these issues requires populations of known differentiated histories, populations on which in turn selection is imposed with contrasting population sizes. The present project involves laboratory populations of Drosophila melanogaster with controlled and replicated histories of selection. The study of their evolutionary dynamics after imposition of new selection regimes, both at small and at large population sizes, as well as later crossing of populations from the same regime, will help resolve the interaction between genetic drift and natural selection, as a function of both previous and present selective and demographic histories.