Evidence for Male-driven Evolution in Drosophila

In several vertebrate taxa studied to date, mutation rates are higher in males than females (male-driven evolution). The male-to-female mutation rate (alpha) can be estimated by contrasting DNA divergence data at X-linked, Y-linked, and autosomal loci. Previous studies in Drosophila, comparing X-linked and autosomal divergence, have found no evidence for male-driven evolution in this genus. Here, I compare levels of nucleotide divergence between homologous X- and Y-linked loci in Drosophila miranda. Using divergence at both synonymous sites and at short introns, I estimate alpha to be approximately 2. This study thus provides the first evidence for male-biased mutation rates outside vertebrates, supporting the view that DNA sequence evolution is male driven in a wide variety of taxa.