Evolutionary insights from a barn swallow chromosome-level assembly

Genomic studies in non-model species are often limited by the lack of chromosome-level, well-annotated reference genomes, which are essential to gain insights into the genomic architecture, variability and evolution of a species. As part of the Vertebrate Genomes Project effort to generate complete and accurate genome assemblies, we present a new reference genome for the European barn swallow Hirundo r. rustica, as well as the first pangenome for the species using five additional Pacbio HiFi assemblies. We employed these genomic resources to investigate the extent of conservation and acceleration among the barn swallow genome and to generate a comprehensive catalogue of genetic markers. LD analyses allowed us to identify several candidate genomic regions under selection. We focussed our analysis on BDNF, a gene with key implications in avian neural differentiation, suggesting a potential methylation-dependent regulatory role of CpG variant sites.