Mitochondrial simple sequenze repeats and 12s – rRNA gene reveal two distinct lineages of Crocidura russula (Mammalia, Sorcidae)

A short segment (135 bp) of the control region and a partialsequence (394 bp) of the 12S-rRNA gene in the mitochondrialDNA of Crocidura russula were analyzed in order to test aprevious hypothesis regarding the presence of a gene flowdisruption in northern Africa. This breakpoint would haveseparated northeast-African C. russula populations fromthe European (plus the northwest-African) populations. Theanalysis was carried out on specimens from Tunisia (C. r. cfagilis), Sardinia (C. r. ichnusae), and Pantelleria (C. r.cossyrensis), and on C. r. russula from Spain and Belgium.Two C. russula lineages were identified; they both shared R2tandem repeated motifs of the same length (12 bp), but not thesame primary structure. These simple sequence repeats werepresent in 12–23 copies in the right domain of the controlregion. Within the northeast-African populations, a polymorphismof repeat variants, not yet found in Europe, was recorded.A neighbor-join tree, which was built by sequences of the conserved 12S-rRNA gene, separated the two sister groups; itpermitted us to date a divergence time of 0.5Myr. Our datadiscriminated two different mitochondrial lineages in accordancewith the previous morphological and karyological data.Ecoclimatic barriers formed during the Middle Pleistocenebroke the range of ancestral species in the Eastern Algeria(Kabile Mountains), leading to two genetically separate andmodern lineages. The northeast-African lineage can today belocated in Tunisia, Pantelleria, and Sardinia. The northwest-African lineage (Morocco and West Algeria), reaching Spainby anthropogenic introduction, spread over north Europe inmodern times. The Palaearctic C. russula species is monophyletic,but a taxonomical revision (ie, to provide a full speciesrank for the northeast taxa and to put in synonymy someinsular taxa) is required.