12:30 p.m., Thursday (January 25, 2007)
University of Vienna
A Multilocus-Multiallele Analysis of Frequency-Dependent Selection Induced by Intraspecific Competition
The study of the mechanisms that maintain genetic variation has a long
history in population genetics. We analyze a multilocus-multiallele
of frequency- and density dependent selection in a large randomly
population. The number of loci and the number of alleles per locus are
arbitrary. The n loci are assumed to contribute additively to a
quantitative character under stabilizing or directional selection
as under frequency-dependent selection caused by intraspecific
competition. We assume the strength of stabilizing selection to be
whereas the strength of frequency dependence may be arbitrary.
Density-dependence is induced by population regulation. Our main
a characterization of the equilibrium structure and its stability
properties in terms of all parameters. It turns out that no
exists with more than two alleles segregating per locus. We give
and sufficient conditions on the strength of frequency dependence to
ensure the maintenance of multilocus polymorphism. We also give
formulas on the number of polymorphic loci maintained at equilibrium.
These results are based on the assumption that selection is
weak compared with recombination, so that linkage equilibrium can be
assumed. If additionally the population size is assumed to be
prove that the dynamics of the model form a generalized gradient
Refreshments will be served at 12:15 p.m. (Lounge, MATX 1115).