Molecular Systematics of the Subfamily Caprinae (Artiodactyla, Bovidae) as Determined from Cytochrome b Sequences

Abstract

We have sequenced the complete mitochondrial DNA cytochrome b gene from 18 species of the subfamily Caprinae and two outgroup taxa. Additional sequences retrieved from the literature were used to constitute a data set of 32 cytochrome b sequences comprising all genera usually included within the Caprinae. Phylogenetic relationships were assessed by PAUP using three new weighting schemes based on homoplasy analyses. Each type of substitution considered at each of the three codon positions was weighted according to its homoplasy level, as measured by the consistency index (CI), the slope of saturation (S), or their product (CIS). These differentially weighted parsimony analyses indicate that (1) the subfamily Caprinae is monophyletic, but only with the exclusion of Saiga from the group; (2) there is no support for monophyly of the four tribes currently recognized (Caprini, Rupicaprini, Ovibovini, and Saigini), suggesting relationships different from those traditionally accepted; (3) the caprine group consists of three major clades corresponding to (a) Budorcas and Ovis, (b) Capricornis, Ovibos, and Naemorhedus, and (c) Capra, Hemitragus, and Pseudois; and (4) the basal branching pattern is very weakly supported by bootstrap or branch support values except for the sister-group relationship of Pantholops with all other caprines, and the phylogenetic positions of Ammotragus, Oreamnos, and Rupicapra remain unclear.