Meeting Abstract
Sex determination is an essential developmental pathway in many animals, yet genes required for sex determination are poorly conserved even between closely related species. Multiple hypotheses have been presented to explain the paradoxically fast evolution of sex determination pathways, but explicit tests of these hypotheses are lacking. The house fly is an ideal model system for testing these hypotheses because multiple different sex determining loci segregate in natural populations, and the distribution of these variants is associated with geographic latitude and some environmental factors. I will present results of experiments using house flies that test hypotheses that could explain the fast evolution of sex determination pathways and identify developmental consequences of evolutionary changes in sex determination. Using population genetic analyses and functional genomic experiments, I have determined that inter-sexual conflict or sex-specific selection pressures are important for the maintenance of polygenic sex determination in house fly. In addition, I show that temperature is an important ecological factor that affects the phenotypes of different house fly sex determining genotypes. These results demonstrate that sex-specific selection pressures are ecologically dependent, and they suggest that a complex interplay of genotype and environment affect the evolution of sex determination.
