Final Report Summary - SEXANTSEL (Determinants of sexually antagonistic selection in a wild mammal population)
Males and females generally need very different attributes to be successful in the battle for survival and reproduction. Indeed, males and females often show large differences in morphology, physiology and behaviour, enabling each sex to successfully survive and reproduce. These sex differences, referred to as sexual dimorphism, could potentially lead to a so-called evolutionary conflict between the sexes: what is good for one sex may be disadvantageous for the other. For example, the two sexes may have different requirements during their early development, even already before birth. In mixed-sex twins, this could lead to male and female embryos having a negative influence on each other’s development in the womb. On a genetic level, the differences between males and females could result in genes that are beneficial to males but may be disadvantageous to females and vice versa. This may lead to opposing selective pressures on these genes depending on whether they are expressed in males or females. Such sexually antagonistic genetic effects may contribute to the maintenance of genetic variation in natural populations despite expected genetic erosion under continual selection. If sexually antagonistic genetic variation is common in nature, this will also have implications for theories of mate choice and sexual selection. Individuals are often thought to choose mates for their ‘good genes’. However, the presence of sexually antagonistic genetic effects could mean that ‘good genes’ in one sex may actually be ‘bad genes’ in the other. In this EU funded Marie Curie Fellowship, I set out to test for the presence of negative interactions between the sexes, focussing on negative influences between twins of different sex and sexually antagonistic genetic effects. The fellowship allowed me to do research at one of the world’s leading centres in evolutionary biology, the Institute of Evolutionary Biology at The University of Edinburgh, UK, and to collaborate with Profs Loeske Kruuk and Josephine Pemberton who are leaders in the field of molecular and quantitative genetics of wild animal populations. In this project, I had the opportunity to use a unique dataset of detailed life-history and pedigree records (dating back to 1985) from a wild population of Soay sheep (Ovis aries) living on the islands of St Kilda, Scotland. An important aim of my fellowship was to also receive training in advanced statistical modelling techniques that use pedigree information to derive estimates of the extent to which different characters may be heritable.