The phylogenetic relationships of Barn swallow (Hirundo rustica) inferred by mitogenomes

Despite available data from bird species are significantly increasing, a comprehensive picture of their phylogenetic relationships is not yet available. This is partially due to the fact that taxonomic classifications can be misled by morphological/behavioural convergence, but especially by the lack of adequate, if any, molecular data from many species. The barn swallow (Hirundo rustica) has a worldwide distribution, in part allowed by the switch from natural nest sites to human structures. Some features such as its fast and highly efficient horizontal flight, long-distance migration, and adaptation to aerial feeding classify this species as particularly interesting for analyses of oxidative phosphorylation genes. Here we provide for the first time the complete mitochondrial genome of the Western Eurasian subspecies H. rustica rustica, by adding four new mitogenomes (sampled in North and Central Italy) to the phylogenetic tree of the Passerines. This pilot project aims to i) fill a gap in the bird mitochondrial DNA tree by adding the first complete mitogenomes of the European barn swallow; ii) clarify the phylogenetic relationships within the H. rustica subspecies complex, within the Passerines, and between Passerines and other similar but non-closely related birds (such as hummingbird and swift - belonging to the order of Apodiformes); iii) search for signals of convergent evolution in the mitochondrial DNA of bird species.