Comparative Population Genomics Reveal the Determinants of Genome Erosion in Two Sympatric Neotropical Falcons

Studying genetic diversity in endangered species has become an important component of conservation science over the past decades. Thanks to recent developments in sequencing technologies and bioinformatics, genetic parameters of conservation relevance such as neutral and functional genome-wide variation are now routinely estimated. Since inbreeding and deleterious mutations represent significant threats to small and declining populations, assessing the dynamics of these parameters has received particular attention in many recent conservation genomics studies. In this issue of Molecular Ecology, Martin et al. analyse the genomes of two Neotropical falcon species to assess the impact of their contrasting population histories on genome-wide diversity. They show that the Orange-breasted falcon which has had a low long-term population size and has experienced recent population bottlenecks is more inbred but has relatively fewer deleterious variations compared to its sister taxon, the Bat falcon, which is characterised by a larger long-term population size. This study not only provides insights into the role of past demography on the dynamics of deleterious variation in two species with contrasting population histories but also highlights the increasing importance of comparative approaches in population and conservation genomics.