EVOLUTIONARY RELATIONSHIPS OF ACOMYS AND OTHER MURIDS (RODENTIA, MAMMALIA) BASED ON COMPLETE 12S RIBOSOMAL-RNA MITOCHONDRIAL GENE-SEQUENCES

Complete rRNA sequences of the mitochondrial 12S gene have been determined for addressing the evolutionary relationships of the spiny mouse (Acomys) with murine, cricetine, and gerbilline muroid rodents. Distance and parsimony analyses have been applied to different kinds of changes (transversions, transitions, gaps). The phylogenetic results suggest that Acomys and Uranomys do not belong to Murinae (a clade containing Mus and Rattus) because Cricetinae (the hamsters Mesocricetus and Cricetulus) appear more related to Murinae than either is to Acomys or Uranomys. Furthermore, Gerbillinae (represented by Tatera and Gerbillus) appear to be an outgroup to the clade comprising Murinae + Cricetinae + Acomys + Uranomys. This result, which is in agreement with immunological data and interpretations, is seriously at odds with traditional systematics based on comparative morphoanatomy. The 12S rRNA sequences give partial support to recent interpretations of Acomys relationships based on nonrepeated DNA/DNA hybridization experiments. The parsimony analysis of nucleotide substitutions in the 12S gene nevertheless indicates that the two competing hypotheses should be retained because they differ from each other by only a very few steps. Additional sequences from other genes (and other taxa of murids) are needed in order to test the significance of the 12S results.