Genetic variation and evolution in the genus Apodemus (Muridae : Rodentia)

Genetic variation was studied using protein electrophoresis of 28-38 gene loci in 1347 specimens of Apodemus agrarius, A. peninsulac, A. flavicollis, A. sylvaticus, A. alpicola, A. uralensis, A. cf. hyrcanicus, A. hermonensis, A. m. mystacinus and A. in. epimelas, representing 121 populations from Europe, the Middle East, and North Africa. Mean values of heterozygosity per locus for each species ranged from 0.02 to 0.04. Mean values of Nei's genetic distance (D) between the taxa ranged from 0.06 (between A. flavicollis and A. alpicola) to 1.34 (between A. uralensis and A. agrarius). The highest values of D were found between A. agrarius and other Apodemus species (0.62-1.34). These values correspond to those generally observed between genera in small mammals. Our data show that A. agrarius and A. peninsulae are sister species, well-differentiated from other taxa. High genetic distance between A. m. mystacinus and A. m. epimelas leads us to consider them distinct species and sister taxa to other Western Palaearctic species of the subgenus Sylvaemus. The data also suggest a recent separation of members of the latter group from a common ancestor, and subsequent rapid radiation, making it difficult to infer phylogenetic relationships. Some taxonomic implications of the results are discussed further. (C) 2002 The Linnean Society of London

The karyotypes of Cryptomys anselli sp. nova and Cryptomys kafuensis sp. nova: new species of the common mole-rat from Zambia (Rodentia, Bathyergidae)

Volume: 64Start Page: 36End Page: 5

G-banded karyotype of the alpine shrew, Sorex alpinus (Mammalia, Soricidae), from the Sumava Mts

The G-banded karyotype of two individuals of the alpine shrew Sorer alpinus collected from the Sumava Mountains (Czech Republic) is presented. The diploid number of chromosomes was 56 and both the morphology and the G-banding pattern of chromosomes appeared to be very similar Gto those reported from the Alps and the Jura Mountains. This is the first report on the G-banded chromosomes of this species outside Switzerland and eastern France

Allozyme variation and systematics of the genus Apodemus (Rodentia : Muridae) in Asia Minor and Iran

Starch gel electrophoresis at 36 presumptive loci was used to study genetic variation and systematic status of 110 wood mice (genus Apodemus) from 19 sites scattered across Anatolia, Armenia, and Iran. Seventeen loci were monomorphic and fixed for the same allele among populations, whereas 19 loci were found to be polymorphic or discriminant among samples. The following species were determined in the material: A. flavicollis, A. uralensis, A. hermonensis, and a taxon provisionally called Apodemus cf. hyrcanicus. The study material was compared with previously analyzed samples from western Anatolia, increasing the total material to 245 specimens from 31 localities. In general, the pattern of variation and level of genetic differentiation within and among species were comparable between western and eastern samples. Intraspecific genetic distances were low, ranging from 0 to 0.051, but interspecific distances were an order of magnitude higher. Similarly, neighbor-joining trees showed negligible differentiation between populations of individual species and no sign of intraspecific structuring. A. uralensis seems to prefer humid sites, whereas A. hermonensis and A. flavicollis also occur in drier places. Individuals referred to Apodemus cf. hyrcanicus were limited to lowlands south of the Caspian Sea. Problems associated with the systematic relationships and taxonomy of A. falzfeini-julvipectus-hermonensis-arianus and A. cf. hyrcanicus from northern Iran are briefly discussed

Allozyme variation and systematics of the genus Apodemus (Rodentia : Muridae) in Asia Minor and Iran

Starch gel electrophoresis at 36 presumptive loci was used to study genetic variation and systematic status of 110 wood mice (genus Apodemus) from 19 sites scattered across Anatolia, Armenia, and Iran. Seventeen loci were monomorphic and fixed for the same allele among populations, whereas 19 loci were found to be polymorphic or discriminant among samples. The following species were determined in the material: A. flavicollis, A. uralensis, A. hermonensis, and a taxon provisionally called Apodemus cf. hyrcanicus. The study material was compared with previously analyzed samples from western Anatolia, increasing the total material to 245 specimens from 31 localities. In general, the pattern of variation and level of genetic differentiation within and among species were comparable between western and eastern samples. Intraspecific genetic distances were low, ranging from 0 to 0.051, but interspecific distances were an order of magnitude higher. Similarly, neighbor-joining trees showed negligible differentiation between populations of individual species and no sign of intraspecific structuring. A. uralensis seems to prefer humid sites, whereas A. hermonensis and A. flavicollis also occur in drier places. Individuals referred to Apodemus cf. hyrcanicus were limited to lowlands south of the Caspian Sea. Problems associated with the systematic relationships and taxonomy of A. falzfeini-julvipectus-hermonensis-arianus and A. cf. hyrcanicus from northern Iran are briefly discussed

Molecular phylogeny of the whole Apodemus genus based on the complete mitochondrial genome and two nuclear genes.

The Apodemus genus is composed of 20 different species distributed throughout the Palearctic region. It is subdivised into two subgenera: - the Sylvaemus subgenus corresponding to the majority of the species living in the Western Part of the Palearctic region; - the Apodemus subgenus, associating most of the Asian species. Although these rodent species are very common and are spread in many European and Asian habitats, their evolutionary history and their phylogenetic relationships are still largely unknown. Previous studies developed on a restricted number of genetic markers and a subset of the Apodemus species gave partial information concerning these aspects. However, many gaps still remain even if such information would be particularly important not only in fundamental taxonomy but also in the field of epidemiology. Indeed many Apodemus species are reservoirs of different pathogens, like the Hantaviruses. A better knowledge of their evolutionary relationships would help to better understand virus spill-overs, which seem to exist among several Apodemus species. The aim of our study was to analyse for the first time in a single research, the totality of the 20 Apodemus species, using as genetic markers, the whole mitochondrial genome as well as two nuclear genes. The phylogenetic analyses based on 20 000 nuclear and mitochondrial DNA base pairs, give a clear pictures of the phylogenetic relationships existing among these species. These results will be compared with the different Hantavirus strains already identified on this rodent group

Sex-specific clines support incipient speciation in a common European mammal

Hybrid zones provide excellent opportunities to study processes and mechanisms underlying reproductive isolation and speciation. Here we investigated sex-specific clines of molecular markers in hybrid zones of morphologically cryptic yet genetically highly-diverged evolutionary lineages of the European common vole (Microtus arvalis). We analyzed the position and width of four secondary contact zones along three independent transects in the region of the Alps using maternally (mitochondrial DNA) and paternally (Y-chromosome) inherited genetic markers. Given male-biased dispersal in the common vole, a selectively neutral secondary contact would show broader paternal marker clines than maternal ones. In a selective case, for example, involving a form of Haldane’s rule, Y-chromosomal clines would not be expected to be broader than maternal markers because they are transmitted by the heterogametic sex and thus gene flow would be restricted. Consistent with the selective case, paternal clines were significantly narrower or at most equal in width to maternal clines in all contact zones. In addition, analyses using maximum likelihood cline-fitting detected a shift of paternal relative to maternal clines in three of four contact zones. These patterns suggest that processes at the contact zones in the common vole are not selectively neutral, and that partial reproductive isolation is already established between these evolutionary lineages. We conclude that hybrid zone movement, sexual selection and/or genetic incompatibilities are likely associated with an unusual unidirectional manifestation of Haldane’s rule in this common European mammal