DNA barcoding and phylogenetic relationships of genera Picoides and Dendrocopos (Aves: Picidae).

Picoides and Dendrocopos are two closely related genera of woodpeckers (family Picidae), and members of these genera have long been the subjects of phylogenetic debate. Mitochondrial cytochrome c oxidase subunit I (COI) is a powerful marker for the identification and phylogenetic study of animal species. In the present study, we analyzed the COI barcodes of 21 species from the two genera, and 222 variable sites were identified. Kimura two-parameter distances were calculated between barcodes. The average interspecific genetic distance was more than 20 times higher than the average intraspecific genetic distance. The neighbor-joining method was used to construct a phylogenetic tree, and all of the species could be discriminated by their distinct clades. Picoides arcticus was the first to split from the lineage, and the other species were grouped into two divergent clades. The results of this study indicated that the COI genetic data did not support the monophyly of Picoides and Dendrocopos.