Title: The genetic basis and evolution of meiotic recombination rate variation -- what have we learned?

Abstract: Meiotic recombination is the exchange of DNA between homologous chromosomes, through chromosomal crossover and gene-conversion events. It is a fundamental feature of sex, and an important driver of diversity in eukaryotic genomes. The toolbox of recombination is remarkably conserved, yet meiotic genes show substantial variation even between closely related species. Furthermore, the rate and distribution of recombination is diverse across eukaryotes, both within and between genomic regions (i.e. "hotspots"), chromosomes, individuals, sexes, populations, and species. In recent decades, major advances have been made in understanding recombination rate variation, in terms of measuring it, identifying its genetic architecture and evolutionary potential, and understanding the complex dynamics of recombination landscapes. In this perspective, written for the 40th anniversary of the journal Molecular Biology and Evolution, I explore what we have learned and are still learning about the genetic basis and evolution of recombination rates, and present open questions for future research.