The effect of temperature on Drosophila hybrid fitness

Mechanisms of reproductive isolation inhibit gene flow between species and can be broadly sorted into two categories: prezygotic and postzygotic. While comparative studies suggest that prezygotic barriers tend to evolve first, postzygotic barriers are crucial for maintaining species boundaries and impeding gene flow that might otherwise cause incipient species to merge. Most, but not all, postzygotic barriers result from genetic incompatibilities between two or more loci from different species, and occur due to divergent evolution in allopatry. Hybrid defects result from improper allelic interactions between these loci. While some postzygotic barriers are environmentally independent, the magnitude of others has been shown to vary in penetrance depending on environmental factors. We crossed D. melanogaster mutants to two other species, D. simulans and D. santomea, and collected fitness data of the hybrids at two different temperatures. Our goal was to examine the effect of temperature on...