CHROMOSOMAL VERSUS MITOCHONDRIAL-DNA EVOLUTION - TRACKING THE EVOLUTIONARY HISTORY OF THE SOUTHWESTERN EUROPEAN POPULATIONS OF THE SOREX-ARANEUS GROUP (MAMMALIA, INSECTIVORA)

The shrews of the Sorer araneus group have undergone a spectacular chr omosome evolution. The karyotype of Sorer granarius is generally consi dered ancestral to those of Sorer coronatus and S. araneus. However, a sequence of 777 base pairs of the cytochrome b gene of the mitochondr ial DNA (mtDNA) produces a quite different picture: S. granarius is cl osely related to the populations of S. araneus from the Pyrenees and f rom the northwestern Alps, whereas S. coronatus and S. araneus from It aly and the southern Alps represent two well-separated lineages. It is suggested that mtDNA and chromosomal evolution are in this case large ly independant processes. Whereas mtDNA haplotypes are closely linked to the geographical history of the populations, chromosomal mutations were probably transmitted from one population to another. Available da ta suggest that the impressive chromosome polymorphism of this group i s quite a recent phenomenon.