Comprehensive DNA barcoding of Italian birds

The Italian peninsula and its Islands host about 540 bird species (287 of which breeding) for a total of 702 subspecies. More than a third are SPECs (Species of European Conservation Concern), 2% are Endangered, 9% are Critically Endangered, and 18% are Vulnerable. In addition, Italy hosts demographically important breeding populations belonging to species of global or regional conservation concern. Nevertheless, knowledge on the genetic diversity of Italian species is still lacking, as only about twenty species were deeply investigated and, before our study, the Barcode of Life Data system (BOLD) hosted only 311 sequences belonging to 31 species and 29 BINs from Italy. It is well known that curated reference DNA barcode libraries are fundamental not only in species-level identification but also in studies on evolution and species diversity at both small and large scales. They are also important for species identification in eDNA metabarcoding approaches, forensic analysis, and conservation projects, for the identification of Management Units (MUs) and Evolutionary Significant Units (ESUs). As part of the BIOURBAN-IMON Project (BaC NBFC spoke 5), we started an extensive sequencing effort of the mitochondrial Cytochrome c Oxidase I (COI) region to provide a comprehensive DNA barcode reference library of the diversity of Italian birds. This work was based on the biological samples included in the two biobanks (tissues with voucher specimens and blood with biometry data) that our research group has developed since 2000s. To date, we have obtained DNA barcoding sequences from more than 200 species of Italian birds; for each species, we have sequenced between 1 and 8 samples distributed across the Italian peninsula, as well as Sicily and Sardinia. Our data leads to an increase of more than 600% of species and 200% of sequences in BOLD. The general intraspecific variation calculated among sequences agrees with literature, but high genetic distance was found in some species, suggesting a possible phylogeographic structure. Our data highlighted the hidden diversity in Italian species and will go on to build a comprehensive library of reference DNA barcodes that will be fertile ground for species-specific in-depth studies on the diversity of Italian and Mediterranean avian populations.