Competition over mating and fertilization opportunities can lead to the evolution of highly elaborate traits like ornaments and weapons, many of which differ between the sexes. I’m interested in the genomic basis of traits under sexual selection, whether they are morphological or molecular in nature.
Are traits that respond to sexual selection fundamentally different from other adaptations, with respect to genomic architecture? For example, are they more likely associated with sex determination pathways, given the possible fitness advantages of phenotypic sex limitation?
What role might sex-specific recombination play in the evolution of sexually selected traits?
Is the main reason reproductive molecules in animals and plants evolve so rapidly because of sexual selection? Syngnathid fishes are a great clade for addressing these questions.
Courting Gulf pipefish (Syngnathus scovelli)
Male-pregnant syngnathid fishes (seahorses, pipefishes, and seadragons), show impressive mating system diversity, and in several lineages sexual selection is markedly stronger on females relative to males. In the photo above, for example, the deeper-bodied, heavily ornamented fish on the right is the female. Such phylogenetic diversity in the strength and direction of sexual selection within this clade presents the opportunity to study the genes and pathways that have responded – perhaps in some cases repeatedly – to strong sexual selection.
As a graduate student I generated the first NGS data for a syngnathid, in order to characterize the transcriptome of the male brood pouch, a novel reproductive tissue. I found that male pregnancy-associated proteins transcribed in the brood pouch evolve at rapid tempos similar to those of Drosophila seminal fluid proteins. Current comparative genomics work is aimed at evaluating the extent to which sexual selection contributes to this pattern. Long-running collaborations with fellow Jones Lab alumni like Bernadette Johnson (now a postdoc in Judith Mank’s lab at UBC) and Sarah Flanagan‘s Lab (U. of Canterbury) are focused on similar questions for other reproductive organs. For example, check out this paper led by Bernadette on the evolution of syngnathid testis transcriptomes!