View Program - 63rd Annual Drosophila Research Conference

Males and females of nearly all sexually reproducing species pursue divergent reproductive strategies to reach their fitness optima despite sharing the same genetic material. These differences can cause intralocus sexual conflict (ISC), where the presence of a shared genetic trait increases fitness in one sex while decreasing fitness in the other sex.
Theoretical and genetic association studies have suggested that ISC can be resolved through the modification of sex-specific gene expression or alternative splicing. However, we still have little empirical evidence of the genes involved in ISC and their direct impact on sex-specific fitness in evolution. A recent study from our laboratory showed for the first time that gene duplication can mitigate sexual conflict in Drosophila melanogaster. The generality of this case is unknown and presents an important problem.
We set out to understand whether intralocus sexual conflict can generally drive the evolution of new genes in Drosophila. We have conducted a CRISPR/Cas9 knockout screen of 36 evolutionarily young, sex-biased gene duplicates in Drosophila. These genes have sex-specific patterns of expression—having high levels of expression in the reproductive tissues of either male or female flies. We have partially assessed the function of half of these duplicates and found that loss-of-function mutations in half of these genes confer a significant reduction in either male or female fertility. Bulk and single-cell RNAseq experiments are being employed to identify the cell types and genetic pathways involved in mitigating sexual conflict in the reproductive tissues. Our preliminary analysis suggests that intralocus sexual conflict drives the evolution of new genes with an unexpectedly large proportion contributing to sex-specific fitness.

Intralocus sexual conflict drives new gene evolution in Drosophila