Molecular systematics of the crackles and allies, and the effect of additional sequence (cyt b and ND2)

Within the New World blackbirds, the lineage of grackles and their allies c ontains several species that have been extremely well studied by avian biol ogists. Using mitochondrial DNA (mtDNA) sequences, we present a phylogeny f or the grackles and allies that serves as a basis for comparative studies i n this group. We compare two gene regions and determine that ND2 is evolvin g more rapidly than cytochrome b. However, this difference in evolutionary rate does not result in significant incongruence between phylogenies derive d from the two gene regions independently A combined weighted analysis prov ides a completely resolved phylogeny for this group. In general, this phylo geny has higher support than the phylogenies derived from the two genes ind ependently. Two major clades are identified in this combined phylogeny (1) a completely South American clade, and (2) a largely North American/Caribbe an/Central American clade. This phylogeny has important implications for th e study of behaviors and morphology.