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The "out of Tibet" hypothesis that suggests an important role of Tibetan highlands in the evolution of Central Asian cold-adapted fauna is a matter of debate. The long-tailed hamster Cricetulus longicaudatus is an important member of both steppe/semidesert Mongolian and high altitude Tibetan faunas. In this study, we analyze the mitochondrial variation in C. longicaudatus throughout a major part of its distribution range, perform molecular dating of the main divergence events, and model its historical range. The data reveal six genetic lineages, which are estimated to have diverged 100–200 kya. Four of the lineages are distributed in the northeastern part of the Qinghai-Tibetan Plateau. The northern part of the distribution range (Mongolia and southern Siberia) is almost entirely populated by another single lineage; its sister haplogroup is restricted to a small isolate in the Xingan Mountains. Species distribution modeling shows that the southern (Chinese) part of the geographic range of C. longicaudatus was relatively stable over the last 200 kya, while the northern (Mongolian) part demonstrated a high level of temporal variation, contracting considerably during cold glacials. The results suggest that the main center of origin of the long-tailed hamster was located in Tibet and that the northern part of the recent range was colonized through a single dispersal event at the Middle–Late Pleistocene boundary. At the same time, the comparative analysis of the fauna of Tibet and Mongolia indicates that the "out of Tibet" model is not the predominant pattern of geographic range evolution for small mammals.

A range-wide phylogeographic study of the common shrew Sorex araneus was performed using the concatenation of cytb and ND2 mitochondrial genes. The data support two major lineages, one of which (European haplogroup) is distributed continuously from West Europe to West Siberia; the other (Siberian haplogroup) is found in two non-adjacent areas: in central Siberia and in southern Finland and Karelia. Several smaller subclades (East European, Balkan, and West Siberian) were identified within the European lineage. Ancestral area reconstructions were performed under the maximum parsimony criterion using the algorithm that was designed to analyze landmark data. The results suggest that the last common ancestor of the common shrew inhabited the Balkans or the Danubian-Carpathian area. The results of demographic analyses are consistent with the hypothesis of recent expansion throughout the entire distribution range. The genetic diversity indices and the expansion time estimates were higher in the western part of the range. Cumulatively, these findings support the hypothesis that during the Last Glacial Maximum, the range of the common shrew was restricted to a single refugium in Southeastern Europe.

The first genetic study of the holotype of the Gansu short-tailed shrew, Blarinella griselda Thomas, 1912, is presented. The mitochondrial analysis demonstrated that the type specimen of B. griselda is close to several recently collected specimens from southern Gansu, northern Sichuan and Shaanxi, which are highly distinct from the two species of Asiatic short-tailed shrews of southern Sichuan, Yunnan, and Vietnam, B. quadraticauda and B. wardi. Our analysis of four nuclear genes supported the placement of B. griselda as sister to B. quadraticauda / B. wardi, with the level of divergence between these two clades corresponding to that among genera of Soricinae. A new generic name, Parablarinella, is proposed for the Gansu short-tailed shrew. Karyotypes of Parablarinella griselda (2n = 49, NFa = 50) and B. quadraticauda (2n = 49, NFa = 62) from southern Gansu are described. The tribal affinities of Blarinellini and Blarinini are discussed.

Karyotype studies of common shrews in the vicinity of Lake Baikal (Irkutsk Region, Eastern Siberia) resulted in the description of two new chromosomal races of Sorex araneus Linnaeus, 1758 (Lypotyphla, Mammalia), additional to 5 races formerly found in Siberia. In the karyotypes of 12 specimens from 3 locations, the polymorphism of metacentric and acrocentric chromosomes of the Robertsonian type was recorded and two distinct groups of karyotypes interpreted as the chromosomal races were revealed. They are geographically distant and described under the racial names Irkutsk (Ir) and Zima (Zi). Karyotypes of both races were characterized by species-specific (the same for all 74 races known so far) metacentric autosomes af, bc, tu and jl, and the typical sex chromosome system – XX/XY1Y2. The race-specific arm chromosome combinations include three metacentrics and four acrocentrics in the Irkutsk race (gk, hi, nq, m, o, p, r) and four metacentrics and two acrocentrics in the Zima race (gm, hi, ko, nq, p, r). Within the races, individuals with polymorphic chromosomes were detected (g/m, k/o, n/q, p/r). The presence of the specific metacentric gk allowed us to include the Irkutsk race into the Siberian Karyotypic Group (SKG), distributed in surrounding regions. The Zima race karyotype contained two metacentrics, gm and ko, which have been never found in the Siberian part of the species range, but appear as the common feature of chromosomal races belonging to the West European Karyotypic Group (WEKG). Moreover, the metacentrics of that karyotype are almost identical to the Åkarp race (except the heterozygous pair p/r) locally found in the southern Sweden. One of two Siberian races described here for the first time, the Zima race, occurs in an area considerably distant from Europe and shares the common metacentrics (gm, hi, ko) with races included in WEKG. This fact may support a hypothesis of independent formation of identical arm chromosome combinations due to occurrence of the same centric fusions in different parts of the species range.

Using a large body of observational data on the occurrence ofSorex shrews in boreal forests, we test two models that predict the structure of small mammal communities along a gradient of increasing habitat productivity. Tilman’s (1982) model predicts a humped curve of species richness along productivity gradients. In contrast, we found a linear increase in species richness with increasing logarithm of the pooled density of shrews, which we use as a measure of habitat productivity for shrews. The model of Hanski and Kaikusalo (1989) assumes a trade-off between exploitative and interference competitive abilities, and it predicts that the size structure of small mammal communities should shift from the dominance of small species (superior in exploitative competition) in unproductive habitats to the dominance of large species (superior in interference competition) in productive habitats. Shrew assemblages show such a shift. Though it is not possible to draw definite conclusions about the role of interspecific competition from our observational data, the changing size structure of local shrew assemblages with increasing habitat productivity is a predictable feature of their community structure.

Authors examined frequency of chromosome aberration in somatic cells in sympatric growin populations of bank vole Clethrionomys glareolus Schreber, 1780 and ruddy vole C. rutilus Pallas, 1779 in central Siberia (Yenisei river island, 62oN, 89'E) from abnormally high flooding which eliminated the previous island populations of the species. The frequency of chromosome aberration increased parallel to the population density of island populations of both species in 1992-1994. In the mainland population of C. rutilus in 1994, the year of low density for this highly cyclic population, significaantly lower frequency of chromosome aberration was found as compared with an island population characterized by high density in this year. The result are interpreted as a disturbance of cytogenetic homeostasis indicating an alteration in an organis'm condition in the overcrowded populations of both species under study.

We examined temporal variation in developmental stability measured by fluctuating asymmetry of 10 skull characters in sympatric populations of three shrew species: Sorex araneus Linnaeus, 1758, S. caecutiens Laxmann, 1788 and S. tundrensis Merriam, 1900 from one locality in central Siberia with a high four-year-cycle of small mammals. Simultaneous significant changes in developmental stability have been revealed during a population cycle 1986-1989 for all three, most abundant shrew species in the locality. The highest asymmetry for all these species occurred in the year of maximal density. Similar high asymmetry was found for the separate samples of two other species: S. roboratus Hollister, 1913 and S. isodon Turov, 1924, collected in a peak year 1989 only. The maximal density in 1989 corresponded to the lowest level of breeding success and developmental stability and, vice versa, minimal density in 1986 was accompanied by the highest level of breeding success and developmental stability. These data suggest that overpopulation caused by high density of various small mammals adversely affects an organism's condition. Thus, developmental stability may be used to monitor possible changes in a population even in cases where direct estimation of fitness is difficult.

We studied temporal changes in the level of phenotypic diversity, measured by the total phenotypic variance for several characters of skull morphology, in two populations of the common shrew Sorex araneus Linnaeus, 1758. We compared a population from central Siberia having a high-amplitude four-year cycle with a population from southern Finland having noncyclic dynamics. The level of total phenotypic diversity varied significantly among years in both populations, but was correlated neither with density nor with breeding success in either of them. We did, however, find differences between the two populations. When we compared changes in the level of phenotypic diversity with changes in the level of developmental stability, as measured by chance developmental variance (fluctuating asymmetry), the cyclic Siberian population exhibited increased developmental variability in the peak year, which was associated with relatively small proportion of other sources of variation (and genetic variation in particular). In other years, the role of chance variation was less and the proportion of other sources of variance was higher. On the other hand, in the noncyclic Finnish population, oscillations in the level of phenotypic diversity were mainly caused by changes in developmental stability. These results illustrate that not only dynamics of genotype variety, but also the alterations in the level of developmental stability can be of great importance for changes in phenotypic diversity.