[en] woodmouse ; Mitochondrial DNA ; cytochrome b ; Western palearctic ; phylogeography
[en] We have sequenced 965 base pairs of the mitochondrial DNA cytochrome b from 102 woodmice (Apodemus sylvaticus) samples collected from 40 European localities. The aims of the study were to answer the following questions: i) Did the Mediterranean peninsulas play a role as a refuge for small mammals? ii) Is the genetic variability of a small mammal like A. sylvaticus higher in the Mediterranean regions as compared with northern Europe? iii)Is it possible to find patterns of postglacial colonisation of Europe other than those presently recognised ? Sequence data were analysed using Distance and Maximum Parsimony phylogenetic reconstruction methods. A minimum spanning network was also calculated. Population genetic structure was determined by analysis of molecular variance (AMOVA). A "mismatch distribution" analysis was also performed to estimate the patterns of expansion. The results provide a clear picture of the impact of Quaternary glaciations on the genetic and geographic structure of the woodmouse. Analyses indicate a higher genetic variability for the woodmouse in the Mediterranean peninsulas as compared to northern Europe and the role of these peninsulas as refuge regions for small mammals. A new pattern of postglacial colonisation is also proposed where the Iberian and southern France refuge populations colonised almost all the European regions. The Sicilian population appears to be highly differentiated and highly variable. This result emphasises the importance of this island as a "hot spot" for the intraspecific genetic diversity of the woodmouse. Finally, populations of this species in North Africa originated from south-western Europe and are probably the result of a recent anthropogenic introduction.
Fonds de la Recherche Scientifique (Communauté française de Belgique) - F.R.S.-FNRS