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

A recent phylogenetic study of the genus Vireo, based on protein elect rophoresis, 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 subgener a Vireo and Lanivireo, a lone taxon containing the species V. bellii a nd a division of the subgenus Vireosylva into a gilvus and an olivaceu s group. To test these results independently, sequence data from the m itochondrial cytochrome b (cyt-b) gene were collected from the followi ng 9 vireos representing the three subgenera: Bell's Vireo (Vireo bell ii), Gray Vireo (V. vicinior), Solitary Vireo (V. solitarius), Black-c apped Vireo (V. atricapillus), White-eyed Vireo (V. griseus), Philadel phia Vireo (V. philadelphicus), Warbling Vireo (V. gilvus), Red-eyed V ireo (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 th e above species, at least 273 homologous base pairs from the cyt-b gen e were amplified using the polymerase chain reaction, and subsequently sequenced. Estimates of phylogenies were achieved through phenetic, m aximum likelihood and weighted cladistic analyses. The evolutionary hi stories produced did not support or reject the monophyly of the genus Vireo. However, Cyclarhis was more closely related to Vireo than was V ireolanius. Two major clades were found in the genus Vireo. An eye-lin ed clade contained members of the subgenus Vireosylva while an eye-rin ged group contained members of the subgenera Vireo and Lanivireo (incl uding V. bellii).