The Rate of Beneficial Mutations Surfing on the Wave of a Range Expansion
PLOS Computational Biology, 8 (3):
1-13 (March 2012)DOI: 10.1371/journal.pcbi.1002447
Abstract
Author Summary When a life form expands its range, the individuals close to the expanding front are more likely to dominate the gene pool of the newly colonized territory. This leads to the sweeping of pioneer genes across the newly colonized, a process which has been named gene surfing. We investigate how this effect interferes with natural selection by evaluating the probability that an advantageous mutant, appearing close to the edge of an advancing population wave, is eventually able to dominate the population range expansion. By numerical simulations and heuristic analysis, we find that the surfing of even strongly beneficial mutations requires that they are introduced with a certain spatial head start compared to the bulk of the population. However, as one moves ahead of the wave, one finds fewer and fewer individuals which can possibly mutate. As a consequence, successful mutations are most likely to arise at an intermediate position in front of the wave. For small selective advantage, the success probability is enhanced by an even smaller amount of genetic drift. This effect could be important in aiding adaptation to local conditions in a range-expansion process.
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