Abstract
Although a number of studies have shown that natural and laboratory populations initially well adapted to their
environment can evolve rapidly when conditions suddenly change, the dynamics of rapid adaptation are not well understood. Here a
population genetic model of polygenic selection is analyzed to describe the short-term response of a quantitative trait after a sudden
shift of the phenotypic optimum. We provide explicit analytical expressions for the timescales over which the trait mean approaches the
new optimum. We find that when the effect sizes are small relative to a scaled mutation rate, small to moderate allele frequency
changes occur in the short-term phase in a synergistic fashion. In contrast, selective sweeps, i.e., dramatic changes in the allele
frequency, may occur provided the size of the effect is sufficiently large. Applications of our theoretical results to the relationship
between QTL and selective sweep mapping and to tests of fast polygenic adaptation are discussed.
Users
Please
log in to take part in the discussion (add own reviews or comments).