Reproductive mode and the evolution of mutation rate

Joëlle Lafond , Srivarshini Saravanakumar, Maurine Neiman, Rebecca A. Zufall, Stephen Wright, Ricardo B. R. Azevedo

The mutation rate is a fundamental force in evolution, modulating patterns of genetic variation, adaptation, and genome evolution throughout the tree of life. As such, many attempts have been made to explain its variation across species. Currently, the dominant theory of mutation rate evolution is the drift-barrier hypothesis. However, although this framework has received wide support across taxa, a substantial fraction of variation in mutation rate remains unexplained, and a major challenge persists in ruling out confounding factors in phylogenetic comparisons. In this review, we propose that transitions in reproductive mode may also be a major factor governing the evolution of mutation rate, through their effects on recombination rates, genetic linkage, and effective population size. We synthesize theoretical predictions and empirical evidence bearing on these effects, highlighting major gaps in our understanding of how reproductive mode influences mutation rate evolution. We argue that progress in this area is now primarily constrained by the need for more realistic theoretical modeling, experimental evolution work, and direct, comparable empirical estimates of mutation rate across diverse taxa and reproductive strategies. Expanding such estimates across taxa will be essential for testing theory and for understanding the extent to which reproductive modes modulate mutation rate evolution.