THE USE OF CYTOCHROME-B SEQUENCE VARIATION IN ESTIMATION OF PHYLOGENY IN THE VIREONIDAE

A recent phylogenetic study of the genus Vireo, based on protein electrophoresis, shows the taxon is polyphyletic and contains four distinct groups. This contradicts the traditional classification of the genus. Johnson et al. (1988) find a group containing members of the subgenera Vireo and Lanivireo, a lone taxon containing the species V. bellii and a division of the subgenus Vireosylva into a gilvus and an olivaceus group. To test these results independently, sequence data from the mitochondrial cytochrome b (cyt-b) gene were collected from the following 9 vireos representing the three subgenera: Bell's Vireo (Vireo bellii), Gray Vireo (V. vicinior), Solitary Vireo (V. solitarius), Black-capped Vireo (V. atricapillus), White-eyed Vireo (V. griseus), Philadelphia Vireo (V. philadelphicus), Warbling Vireo (V. gilvus), Red-eyed Vireo (V. olivaceus) and Black-whiskered Vireo (V. altiloquus), and two confamilial species: Rufous-browed Peppershrike (Cyclarhis gujanensis) and Slaty-capped Shrike-Vireo (Vireolanius leucotis). For each of the above species, at least 273 homologous base pairs from the cyt-b gene were amplified using the polymerase chain reaction, and subsequently sequenced. Estimates of phylogenies were achieved through phenetic, maximum likelihood and weighted cladistic analyses. The evolutionary histories produced did not support or reject the monophyly of the genus Vireo. However, Cyclarhis was more closely related to Vireo than was Vireolanius. Two major clades were found in the genus Vireo. An eye-lined clade contained members of the subgenus Vireosylva while an eye-ringed group contained members of the subgenera Vireo and Lanivireo (including V. bellii).