SConCichlid · Genomic basis of sexual dimorphism, sexual conflict and male ornament variation

Sexual selection is one of the major drivers for the evolution of striking phenotypes such as male ornaments contributing to sexual dimorphism in many species. These phenotypes represent some of the most remarkable within-species variation and primarily result from a shared genome between sexes. This may lead to genomic conflicts between males and females arising due to divergent reproductive fitness or survival optima for each sex and have profound implications for genome and trait evolution. Such sexual conflict can hinder the ability of species to evolve towards trait optima, but has also been hypothesized to contribute to the maintenance of genetic variation through balancing selection thereby enhancing their adaptive potential. Despite this, the mechanisms underlying the development of sexually dimorphic traits, the nature and extent of sexual conflict and its role in shaping genetic and morphological diversity remain poorly understood. In this project, I propose to study the genetic and developmental mechanisms underpinning the sexually dimorphic traits using a powerful model system of a cichlid species Astatotilapia calliptera. I will perform RNA-seq and ATAC-seq of different tissue types, sex, and ecomorphs of A. calliptera to identify the genes and gene regulatory machinery involved in the development of sexually dimorphic traits. Next, I will perform whole-genome sequencing of 600 individuals to identify genetic loci under potential sexual conflict by testing for intersexual allelic divergence and balancing selection across the genome. Finally, I will use genome-wide association methods to uncover the phenotypic effects of sexually antagonistic variation throughout development and life history, and determine if sexual conflict contributes to maintaining genetic and morphological variation, particularly in sexually selected male ornaments. This study will profoundly impact our understanding of the mechanisms underlying organismal development and diversity.