Abstract

The advantages of genetic recombination are well known, but some situations have led to its suppression. I will show how ideas about the evolution of mimicry in butterflies led to an understanding of how the evolution of complex adaptations, that are built up in several evolutionary steps, may select for suppressed recombination, and how this understanding illuminates the evolution of sex chromosomes. Although the theoretical work involved in understanding these situations was done many years ago, recent developments in molecular methods are allowing empirical studies to test the hypotheses involved, even though the best species for these tests are non-model animal and plant species. I will particularly focus on the value of plants for studying the evolution of non-recombining Y chromosomes, including estimating the age when different systems evolved, and the time-course of recombination suppression across the sex chromosome pair. I will discuss the sexual antagonism hypothesis for recombination suppression, and how it may be tested in evolving sex chromosome systems.