Dissertation Research: Evolutionary Genetics of the Speciation Gene, Maternal Hybrid Rescue

University Of Rochester, Rochester NY

Investigators

Abstract

Speciation - the splitting of one species into two - creates biodiversity. As two interbreeding populations evolve mechanisms preventing the exchange of genes, they become new species with independent evolutionary fates. Genetic exchange between species is often limited by the sterility or inviability of their hybrids. At least in animals, such hybrid problems are caused by genetic incompatibilities: some genes from species A no longer function properly with those of species B when brought together in hybrids. The work proposed here will investigate the genes that cause hybrid inviability between species of the fruitfly Drosophila. Using the genetic and developmental techniques available in these model organisms, the project will first identify the DNA sequences of genes that miscommunicate in hybrids and, second, characterize their lethal interaction. The experiments will focus on the role of one candidate "speciation gene", maternal hybrid rescue. Once identified at the molecular level, one can then ask how the sequences of such genes changed between species, why their products fail to properly interact in hybrids, and what evolutionary forces drove their divergence. Only by genetically dissecting hybrid problems can biologists begin to understand the evolution of genetic incompatibilities and thus the origin of new species.