In this week’s issue of Science, geneticists discuss the genetic control of hotspots ― the preferred chromosomal locations for meiotic recombination events. Vivian Cheung, a Howard Hughes Medical Institute investigator, and her colleagues discuss three papers appearing in the issue that identify a mammalian gene, PRDM9, which appears to control the extent to which crossovers occur at hotspots. PRDM9 codes for a zinc-finger protein of the same name, which has shown to be highly polymorphic.