Document: CHA-3-47-3

Ecological determinants of small-scale genetic structure in plants.

LEE, C.T.*

University of California, Davis, CA 95616, U.S.A. ¹

Abstract:
Standard models of isolation-by-distance show that small-scale genetic structure at neutral loci results from restricted dispersal within continuous populations. The shape of the distribution of individuals around their parents has largely been considered unimportant in comparison to the spatial extent of dispersal, which is measured by the variance of the distribution. Using a stochastic, individual-based simulation of a population of annual plants, I show that the shape of the dispersal distribution does affect patterns of small-scale genetic structure under reasonable biological conditions. Spatial autocorrelation statistics indicate that genetic structure depends on a complex interaction between the extent of dispersal, the shape of the dispersal distribution, and the average fecundity of individuals in the population: If fecundity is high enough, the effects of changing the extent of dispersal depend on the kurtosis of the dispersal distribution. Self-incompatibility and the presence of a seed bank modify this interaction. These results suggest that the inference of dispersal parameters from patterns of genetic relatedness is subtantially complicated by other aspects of the ecology of the species in question.

Keywords:

This abstract is being presented at: 2:15 PM in session:
Oral Session #63: Evolutionary Ecology.