Investigating trade-offs in sexual populations with gene flow

Understanding the processes underlying trade-offs between environments, where adaptation to one results in decreased fitness in another, is important in understanding evolutionary processes across a wide range of organisms. The molecular basis of this evolutionary phenomenon is a key question in biology generally. Unravelling the basis of trade-offs has application in understanding the maintenance of sexual reproduction in most eukaryotic lineages in spite of apparent costs. In this chapter, we discuss the evolutionary problem of sexual reproduction, and its relationship with trade-offs, working from August Weismann’s suggestion that sex improves the efficiency of natural selection. We argue that microbial experimental evolution is an important way in which claims about trade-offs and sex can be tested and that these experiments need to be developed to better represent real world ecological and evolutionary problems. We review experiments, including from our laboratory, which bear on the question of the benefits of sex in complex environments. We also argue for the necessity of a genomic rather than merely genetic perspective on these questions