Reversed sex-biased mutation rates for indels and base substitutions in Drosophila melanogaster

Sex biases in mutation rates may affect the rate of adaptive evolution. In many species, males have higher mutation rates than females when single nucleotide variants (SNVs) are considered. In contrast, indel mutations in humans and chimpanzees are female-biased. In Drosophila melanogaster, direct estimates of mutation rates did not uncover sex differences, but a recent analysis suggested the presence of male-biased SNVs mutations. Here we study the sex-specific mutation processes using mutation accumulation data from mismatch-repair deficient D. melanogaster. We find that sex differences in flies are similar to the ones observed in humans: a higher mutation rate for SNVs in males and a higher indel rate in females. These results have major implications for the study of neutral variation and adaptation in Drosophila.