title: c-mos variation in songbirds: molecular evolution, phylogenetic implications, and comparisons with mitochondrial differentiation.
abstract: Nucleotide sequences from the c-mos proto-oncogene have previously been used to reconstruct the phylogenetic relationships between distantly related vertebrate taxa. To explore c-mos variation at shallower levels of avian divergence, we compared c-mos sequences from representative passerine taxa that span a range of evolutionary differentiation, from basal passerine lineages to closely allied genera. Phylogenetic reconstructions based on these c-mos sequences recovered topologies congruent with previous DNA-DNA hybridization-based reconstructions, with many nodes receiving high support, as indicated by bootstrap and reliability values. One exception was the relationship of Acanthisitta to the remaining passerines, where the c-mos-based searches indicated a three-way polytomy involving the Acanthisitta lineage and the suboscine and oscine passerine clades. We also compared levels of c-mos and mitochondrial differentiation across eight oscine passerine taxa and found that c-mos nucleotide substitutions accumulate at a rate similar to that of transversion substitutions in mitochondrial protein-coding genes. These comparisons suggest that nuclear-encoded loci such as c-mos provide a temporal window of phylogenetic resolution that overlaps the temporal range where mitochondrial protein-coding sequences have their greatest utility and that c-mos substitutions and mtDNA transversions can serve as complementary, informative, and independent phylogenetic markers for the study of avian relationships.
authors.affiliation: Smithsonian Tropical Research Institute, Panamà. ilovette@sas.upenn.edu
authors.forename: I J
authors.initials: IJ
authors.lastname: Lovette
authors.forename: E
authors.initials: E
authors.lastname: Bermingham
mesh_terms: D000818:Animals; D001482:Base Composition; D002467:Cell Nucleus / Q000235:genetics; D019143:Evolution, Molecular; D014644:Genetic Variation; D008928:Mitochondria / Q000235:genetics*; D010802:Phylogeny; D017231:Proto-Oncogene Proteins c-mos / Q000235:genetics*; D020308:Songbirds / Q000145:classification* / Q000235:genetics*
chemical_list: D017231:Proto-Oncogene Proteins c-mos