Nature, Published online: 22 January 2025; doi:10.1038/d41586-025-00098-zHuman genetic diversity and evolution rely on new mutations and exchange of DNA between chromosomes during the generation of sex cells, in a process called recombination. Recombination manifests as large-scale crossovers, and as short-scale transitions called non-crossovers. A map of where recombination occurs throughout the human genome now includes both types of variation.