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 determ ined for addressing the evolutionary relationships of the spiny mouse (Acomys) with murine, cricetine, and gerbilline muroid rodents. Distan ce and parsimony analyses have been applied to different kinds of chan ges (transversions, transitions, gaps). The phylogenetic results sugge st that Acomys and Uranomys do not belong to Murinae (a clade containi ng Mus and Rattus) because Cricetinae (the hamsters Mesocricetus and C ricetulus) appear more related to Murinae than either is to Acomys or Uranomys. Furthermore, Gerbillinae (represented by Tatera and Gerbillu s) appear to be an outgroup to the clade comprising Murinae + Cricetin ae + Acomys + Uranomys. This result, which is in agreement with immuno logical data and interpretations, is seriously at odds with traditiona l systematics based on comparative morphoanatomy. The 12S rRNA sequenc es give partial support to recent interpretations of Acomys relationsh ips based on nonrepeated DNA/DNA hybridization experiments. The parsim ony 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 sequ ences from other genes (and other taxa of murids) are needed in order to test the significance of the 12S results.