Social adaptation across the genome : trade-offs and conflicts in relation to sex

Abstract

Natural selection explains both how and why biological organisms appear well adapted to their environments. Some of the most successful tests of our understanding of adaptation have focused on two phenomena: trade-offs, when organisms have to simultaneously optimise multiple conflicting objectives; and conflicts, when organisms – or their constituent genes – have different inclusive fitness agendas. In this thesis, I explore both of these phenomena, with a particular focus on problems relating to sex. Part I focuses on trade-offs between female and male fitness. I consider how different genetical systems, sexual ecologies, and life-history details modulate the relative weights placed on female and male fitness, and thus generate biases concerning the fates of such sexually antagonistic alleles. Part II focuses on conflicts within the genome which may emerge when genes differ in how they flow between males and females. Combined with sex-specific aspects of demography and ecology, this may result in genes placing different values upon the fitness of their carrier and social partners. I explore a series of such models, considering how intragenomic conflicts may emerge over various intersexual and intrasexual social behaviours.