THE COMPLETE MITOCHONDRIAL-DNA SEQUENCE OF THE GREATER INDIAN RHINOCEROS, RHINOCEROS-UNICORNIS, AND THE PHYLOGENETIC RELATIONSHIP AMONG CARNIVORA, PERISSODACTYLA, AND ARTIODACTYLA (PLUS CETACEA)

The sequence (16,829 nt) of the complete mitochondrial genome of the g reater Indian rhinoceros, Rhinoceros unicornis, was determined. Like o ther perissodactyls studied (horse and donkey) the rhinoceros demonstr ates length variation (heteroplasmy) associated with different numbers of repetitive motifs in the control region. The 16,829-nt variety of the molecule includes 36 identical control region motifs. The evolutio n of individual peptide-coding genes was examined by comparison with a distantly related perissodactyl, the horse, and the relationships amo ng the orders Carnivora, Perissodactyla, and Artiodactyla (+ Cetacea) were examined on the basis of concatenated sequences of 12 mitochondri al peptide-coding genes. The phylogenetic analyses grouped Carnivora, Perissodactyla, and Artiodactyla (+ Cetacea) into a superordinal clade and within this clade a sister group relationship was recognized betw een Carnivora and Perissodactyla to the exclusion of Artiodactyla (+ C etacea). On the basis of the molecular difference between the rhinocer os and the horse and by applying as a reference the Artiodactyl/Cetace an divergence set at 60 million years ago (MYA), the evolutionary dive rgence between the families Rhinocerotidae and Equidae was dated to ap proximate to 50 MYA.