MOLECULAR EVOLUTIONARY DYNAMICS OF CYTOCHROME-B IN STREPSIRRHINE PRIMATES - THE PHYLOGENETIC SIGNIFICANCE OF 3RD-POSITION TRANSVERSIONS

DNA sequences of the complete cytochrome b gene are shown to contain r obust phylogenetic signal for the strepsirrhine primates (i.e., lemurs and lorises). The phylogeny derived from these data conforms to other molecular studies of strepsirrhine relationships despite the fact tha t uncorrected nucleotide distances are high for nearly all intrastreps irrhine comparisons, with most in the 15%-20% range. Cytochrome b sequ ences support the hypothesis that Malagasy lemuriforms and Afro-Asian lorisiforms each comprise clades that share a sister-group relationshi p. A study (Adkins and Honeycutt 1994) of the cytochrome c oxidase sub unit II (COII) gene placed one Malagasy primate (Daubentonia) at the b ase of the strepsirrhine clade, thereby suggesting a diphyletic Lemuri formes. The reanalysis of COII third-position transversions, either al one or in combination with cytochrome b third-position transversions, however, yields a tree that is congruent with phylogenetic hypotheses derived from cytochrome b and other genetic data sets.