A MULTIGENE ASSESSMENT OF PHYLOGENETIC-RELATIONSHIPS WITHIN THE DASYURID MARSUPIAL SUBFAMILY SMINTHOPSINAE

We report sequences of the mitochondrial cytochrome b (1146 bp) and 12 5 rRNA (961 bp) genes, as well as the nuclear protamine P1 (608 bp) ge ne, from 13 species representing all four genera of the dasyurid marsu pial subfamily Sminthopsinae. Mitochondrial sequences are partitioned into five categories (three codon positions in cytochrome b, and stems and loops in 12S rRNA) with distinct substitution rates, transition b iases, and base compositions. We extract estimates of these biases fro m the sequences and employ them to calculate two overall distances bas ed on the DNAML model. Phylogenetic analyses using distance and parsim ony methods yield trees with different topologies for mtDNA and protam ine. These trees are compatible with respect to highly resolved nodes, but incompatible with respect to length differences in a parsimony fr amework. The tree from combined-data analysis is dominated by the larg er data set (mtDNA). The balance of evidence favors a basal separation of Planigale from other sminthopsines. Within Planigale, Pl. maculata is sister to the remaining species. Although the precise intergeneric affinities of Antechinomys are unresolved, A. laniger does not appear to be part of the genus Sminthopsis as suggested by morphological dat a. The 12S rRNA resolves Ningaui ridei and N. yvonnae assister species . (C) 1997 Academic Press.