DNA BARCODES PROVIDE NEW EVIDENCE OF A RECENT RADIATION IN THE GENUS SPOROPHILA

CAMPAGNA, LEONARDO; LIJTMAER, DARÍO A.; KERR, KEVIN C. R.; BARREIRA, ANA S.; HEBERT, PAUL D. N.; TUBARO, PABLO L.

AUK

Año: 2008

0004-8038

The capuchinos are a monophyletic clade in the genus Sporophila that has radiated very recently, as evidenced by their lack of mitochondrial genetic diversity. In this study, cytochrome c oxidase I (COI) sequences (or DNA barcodes) were obtained for six of the seven species of southern capuchinos found in Argentina. Patterns of COI variability in this group were compared to those observed in other Argentine bird species. The COI sequences were also subjected to maximum parsimony and maximum likelihood phylogenetic analyses. The average interspecific divergence within the southern capuchinos was closer to the average divergence detected within Argentine species rather than between them. Moreover, the COI clusters of the southern capuchinos overlap as haplotypes were shared between most species. As expected from these results, phylogenetic analyses using COI sequences produced a polytomy. The southern capuchinos constitute the only multi-species group that cannot be separated by DNA barcodes among the species of Argentine birds barcoded so far. Similar cases have been observed only in the large white headed gulls, Darwin’s finches and possibly the crossbills (Loxia spp.). Extending the analysis to genetic markers with higher rates of evolution will be crucial to understanding this unique radiation.Sporophila that has radiated very recently, as evidenced by their lack of mitochondrial genetic diversity. In this study, cytochrome c oxidase I (COI) sequences (or DNA barcodes) were obtained for six of the seven species of southern capuchinos found in Argentina. Patterns of COI variability in this group were compared to those observed in other Argentine bird species. The COI sequences were also subjected to maximum parsimony and maximum likelihood phylogenetic analyses. The average interspecific divergence within the southern capuchinos was closer to the average divergence detected within Argentine species rather than between them. Moreover, the COI clusters of the southern capuchinos overlap as haplotypes were shared between most species. As expected from these results, phylogenetic analyses using COI sequences produced a polytomy. The southern capuchinos constitute the only multi-species group that cannot be separated by DNA barcodes among the species of Argentine birds barcoded so far. Similar cases have been observed only in the large white headed gulls, Darwin’s finches and possibly the crossbills (Loxia spp.). Extending the analysis to genetic markers with higher rates of evolution will be crucial to understanding this unique radiation.