I study genetic differentiation and evolution in structured populations. My research combines theoretical and experimental approaches to study the effects of selection among individuals, populations and communities. One of my major areas of interest is how certain types of genetic variation, such as epistatic interactions among loci, can contribute to a response to selection in a subdivided population even though they cannot contribute to a response to selection in a large panmictic population. My current research includes (1) the effect of founder events and population structure on genetic variance, (2) theoretical and experimental studies of multilevel selection, and (3) evolution and speciation in spatially structured populations. The techniques I use are drawn from the field of quantiative genetics and molecular quantitative genetics. My experimental work uses the resemblance among relatives and the response to selection to study the genetic basis of complex traits. My theoretical work uses statistical and quantitative genetic methods to study evolution in subdivided populations.
Selected Publications
The additive genetic variance as a function of migration rate for different forms of genetic effects. Note that for gene interactions the additive genetic variance is maximized at one migrant every two to four generations.
The potential role of epistasis in speciation can be illustrated with dominance by additive epistasis. In a population segregating for the A locus, but fixed for the B2 allele the A locus will be overdominant. If a B1 allele is introduced into the metapopulation either by mutation or migration it will initially be neutral, however genetic drift at the A locus will result in directional selection favoring the B1 allele (II left and right columns). Eventually this will drive the population to fixation of the B1 allele, and one of the two A alleles.