The Drosophila simulans Y chromosome interacts with the autosomes to influence male fitness.

Abstract

The Y chromosome should degenerate because it cannot recombine. However, male limited transmission increases selection efficiency for male benefit alleles on the Y, and therefore Y-chromosomes should contribute significantly to variation in male-fitness. This means that although the Drosophila Y chromosome is small and gene-poor, Y-linked genes are vital for male fertility in D. melanogaster and the Y chromosome has large male-fitness effects. It is unclear if the same pattern is seen in the closely related D. simulans. We backcrossed Y chromosomes from 3 geographic locations into 5 genetic backgrounds and found strong Y and genetic background effects on male fertility. There was a significant Y-background interaction, indicating substantial epistasis between the Y and autosomal genes affecting male fertility. This supports accumulating evidence that interactions between the Y chromosome and the autosomes are key determinants of male fitness. This article is protected by copyright. All rights reserved.