Genetics of Sexual Antagonism

The phrase “two sexes, one genome” nicely sums up the evolutionary problem that all dioecious species must face. The existence of separate sexes, by definition, results in a population where individuals are forced to follow one of two routes to maximize fitness. These routes are frequently divergent and yet, both sexes rely on virtually the same shared genetic material from which they build their phenotype. That males and females look and behave differently did not escape Darwin, and he devoted much of his book The Descent of Man to cataloging the diverse forms and behaviours seen throughout the animal kingdom (his “secondary sexual characters”). But the evolution of this sexual dimorphism remains largely unexplained. Research in our lab aims to learn more about how sexual antagonism (a.k.a. intralocus sexual conflict) can contribute to the evolution of sexual dimorphism.

Thanks to a century of research into the genetics of the fruit fly we know a great deal about the Drosophila genome, the function and location of the genes it contains, and where those genes are expressed. Research into sexual conflict has been going on for a much shorter period of time and has so far been undertaken at the level of the whole organism to answer relatively simple questions such as does sexual conflict exist, and what is the basis of the antagonism? My lab currently takes a reductionist approach to learn more about the genetics of sexual conflict by taking the tricks and tools developed by fly geneticists and using them within an evolutionary context. In this way we can test predictions made by sexual conflict theory (e.g. are sexually antagonistic genes over-represented on the X-chromosome?) and learn more about which biological processes are affected by this form of selection. There is a long way to go before we fully understand the evolutionary process of sexual antagonism but we believe modern genomic tools will help us make significant advances.