Part of the 2013–2014 Fellows Presentation Series
Population waves have played a crucial role in evolutionary history, as in the “out of Africa” hypothesis for human ancestry. Population geneticists and physicists are now developing methods for understanding how mutations, number fluctuations, and selective advantages play out in such situations. Once the behavior of pioneer organisms at frontiers is understood, genetic markers can be used to infer information about growth, ancestral population size, and colonization pathways. Insights into the nature of competition and cooperation at frontiers are possible. Neutral mutations optimally positioned at the front of a growing population wave can increase their abundance by “surfing” on the population wave. David R. Nelson will present experimental and theoretical studies of this effect, using bacteria and yeast as model systems.