Papilio phylogeny based on mitochondrial cytochrome oxidase I and II genes

Butterflies of the genus Papilio have served as the basis for numerous stud ies in insect physiology, genetics, and ecology, However, phylogenetic work on relationships among major lineages in the genus has been limited and in conclusive. We have sequenced 2.3 kb of DNA from the mitochondrial cytochro me oxidase I and II genes (COI and COII) for 23 Papilio taxa and two outgro ups, Pachliopta neptunus and Eurytides marcerllus, in order to assess the p otential of these genes for use in Papilio phylogenetics and to examine? pa tterns of gene evolution across a broad taxonomic range. Nucleotide and ami no acid variation is distributed heterogeneously, both within and between g enes, Structural features of the proteins are not always reliable predictor s of variation. In a combined analysis, these sequences support a nearly fu lly resolved topology within subgenera and species groups, though higher le vel relationships among species groups require additional study. The! most noteworthy findings are that neither Papilio alexanor nor P. xuthus belongs in the machaon group and that the subgenus Pterourus is paraphyletic with respect to the subgenus Pyrrhosticta. We leave relationships among members of the pliorcas species group as a trichotomy. These two protein coding gen es, particularly COI, show excellent performance in resolving relationships at the level of species and species groups among Papilionidae. We strongly endorse a similar approach for future studies aimed at these levels. (C) 1 999 Academic Press.