We show the fine-scale recombination landscape is stable across tens of millions of years in birds, in sharp contrast to what is seen in primates and mice.. Stable recombination hotspots in birds

The DNA-binding protein PRDM9 has a role specifying meiotic recombination hotspots in mice and apes, but appears to be absent from other vertebrate species, including birds. To study the evolution and determinations of recombination in species lacking PRDM9, we inferred fine-scale recombination maps from population resequencing data for two bird species, the zebra finch Taeniopygia guttata, and the long-tailed finch, Poephila acuticauda, who are as divergent as humans and chimpanzees. We find that both bird species have hotspots, which are enriched near CpG islands and transcription start sites. Unlike what is observed in mice and apes, the two species share most hotspots, with indirect evidence suggesting hotspots are conserved across tens of millions of years. These observations link the evolution of hotspots to their genetic architecture, suggesting that in the absence of PRDM9, accessibility of the genome to cellular recombination machinery, particularly around functional genomic elements, both enables increased recombination and constrains its evolution.