Meiotic recombination is targeted in the genome by the creation of double-strand breaks (DSBs) at recombination ‘hotspots’. At least two mechanisms are known to be involved. Hoge et al. report that these mechanisms are not mutually exclusive and that differences between species in the recombination landscape reflect the balance of competition between them.

The authors first improved the corn snake reference genome and the annotation of transcription start sites and CpG islands. Genomes from 37 snakes were sequenced, and 24 snakes that were not close relatives were analysed for SNPs. Using this genetic variation, patterns of linkage disequilibrium (LD) were used to infer a population recombination map of the genome.