Catch me if you can: Adaptation from standing genetic variation to a moving phenotypic optimum

Date(s) : 24/06/2015   iCal
11 h 00 min - 12 h 00 min

Adaptation lies at the heart of Darwinian evolution. Natural populations are constantly faced with environmental changes that force them to either adapt or go extinct – a problem that is aggravated by human-induced global change. Therefore, increasing our understanding of the adaptive process is important for both basic and applied research.

Accordingly, numerous studies have tried to provide a formal framework for the description of the adaptive process. Out of these, two complementary modeling approaches have emerged: While so-called adaptive-walk models consider adaptation from the successive fixation of de-novo mutations only, quantitative genetic models, on the other hand, assume that adaptation proceeds exclusively from pre-existing standing genetic variation. The latter approach, however, has focused on short-term evolution of population means and variances rather than on the statistical properties of adaptive substitutions.

Thus, I will here address what has been described as “the most obvious theoretical limitation when describing the adaptive process” and propose an analytical framework for the genetic basis of adaptation from standing genetic variation in terms of the effect-size distribution of individual alleles.

This approach addresses one of the central questions in this context: From the multitude of standing genetic variants segregating in a population, which are the ones that ultimately become fixed and contribute to adaptation, and how does their distribution differ from that of de-novo mutations?



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