So close and so different: comparative phylogeography of two small mammal species, the yellow-necked fieldmouse (Apodemus flavicollis) and the woodmouse (Apodemus sylvaticus) in the Western Palearctic region.

In Europe, concordant geographical distribution among genetic lineages within different species is rare, which suggests distinct reactions to Quaternary ice ages. This study aims to determine whether such a discrepancy also affects a pair of sympatric species, which are morphologically and taxonomically closely related but which have slight differences in their ecological habits. The phylogeographic structures of two European rodents, the Yellow-necked fieldmouse (A. flavicollis) and the woodmouse (Apodemus sylvaticus) were, therefore, compared on the basis of mitochondrial DNA cytochrome b (mtDNA cyt b) sequences (965 base pairs) from 196 specimens collected from 59 European localities spread throughout the species distributions. The results indicate that the two species survived in different ways through the Quaternary glaciations. A. sylvaticus survived in the Iberian Peninsula from where it recolonized almost all Europe at the end of the last glaciation. Conversely, the refuge from which A. flavicollis recolonized Europe, including northern Spain, during the Holocene corresponds to the Italo-Balkan area, where A. sylvaticus suffered a serious genetic bottleneck. This study confirms that even closely related species may have highly different phylogeographic histories and shows the importance of ecological plasticity of the species for their survival through climate change. Finally, it suggests that phylogeographic distinctiveness may be a general feature of European species

Origin and genome evolution of polyploid green toads in Central Asia: evidence from microsatellite markers.

Polyploidization, which is expected to trigger major genomic reorganizations, occurs much less commonly in animals than in plants, possibly because of constraints imposed by sex-determination systems. We investigated the origins and consequences of allopolyploidization in Palearctic green toads (Bufo viridis subgroup) from Central Asia, with three ploidy levels and different modes of genome transmission (sexual versus clonal), to (i) establish a topology for the reticulate phylogeny in a species-rich radiation involving several closely related lineages and (ii) explore processes of genomic reorganization that may follow polyploidization. Sibship analyses based on 30 cross-amplifying microsatellite markers substantiated the maternal origins and revealed the paternal origins and relationships of subgenomes in allopolyploids. Analyses of the synteny of linkage groups identified three markers affected by translocation events, which occurred only within the paternally inherited subgenomes of allopolyploid toads and exclusively affected the linkage group that determines sex in several diploid species of the green toad radiation. Recombination rates did not differ between diploid and polyploid toad species, and were overall much reduced in males, independent of linkage group and ploidy levels. Clonally transmitted subgenomes in allotriploid toads provided support for strong genetic drift, presumably resulting from recombination arrest. The Palearctic green toad radiation seems to offer unique opportunities to investigate the consequences of polyploidization and clonal transmission on the dynamics of genomes in vertebrates