Identifying genes that underly reproductive isolation is critical for the understanding of the mechanisms responsible for the production and maintenance of biological variation. Many reproductive isolating genes have been discovered in a handful of species, but their specific actions are relatively unknown. Namely, this is due to the fact that many isolating factors evolve during the process of speciation, and it is impossible to pinpoint the most important ones without knowing the distribution of fitness effects of all factors and their mutation order. In the case of postzygotic isolation, the phenotype is that of reduced or zero fitness in a hybrid. The genetic architecture, or genotype-phenotype map for a hybrid individual may be a complex distribution of epistatic, polygenic, and pleiotropic effects.
I am currently working on mapping the genes responsible for hybrid inviability (reduced fitness) between populations of Tribolium castaneum. At such an early stage and with relatively little divergence, it is possible to identify interacting factors, where few exist. I am currently constructing recombinant congenic lines that will be either RAD sequenced or whole genome sequenced in order to identify the underlying nucleotide residues.