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Variation of the 838-bp fragment of the mitochondrial cytb gene was analyzed in Sylvaemus uralensis from the northern macroslope of the Western Caucasus. On the basis of two fixed nonsynonymous substitutions, cytb sequences of the population sample studied can be considered as a distinct Lago-Naki haplogroup, which is clustered in the European cytb lineage. As estimated on the basis of the known rate of substitutions per third codon position in S. sylvaticus, the population must have been isolated for all or a part of the last glaciation period (10000 to 100000 years ago). The observed differentiation of cytb haplotypes is indicative of the refugial distribution of S. uralensis in the northern macroslope of the Western Caucasus, as well as of a secondary contact between the Caucasian and the Russian Plain populations during the Holocene. [ABSTRACT FROM AUTHOR]

In this work the genetic variability of the common shrew populations Sorex araneus L. in Eastern Europe was studied via sequencing of the mitochondrial gene cyt b. A total of 82 sequences of the mitochondrial gene cyt b with a length of 953 basepairs were analyzed, including five chromosome races in a continuous area of the species in forest zone and two races in fragmented area in the steppe zone. Phylogeographic subdivision of the common shrew was not expressed, and there was no significant correlation between genetic and geographic distances in continuous areas. We did not acquire convincing evidence of the influence of narrow hybrid zones between chromosome races on the flow of neutral alleles. A significant p-distance (0.69 ± 0.27%) of geographically close populations of the chromosome race Neroosa indicates the formation of the karyotype of this race in the Pliocene or Pleistocene. In our work, the phylogeographic structure was determined more by species area fragmentation than by its karyotypic features.

To ascertain intra- and interspecific differentiation patterns of some Sylvaemus wood mice species (S. uralensis, S. sylvaticus, S. ponticus, S. flavicollis, and S. fulvipectus), sequence variation of the mitochondrial cytochrome oxidase subunit I gene (COI) fragment (654 bp) was analyzed and the data obtained using several molecular genetic markers were compared. Distinct isolation of all Sylvaemus species (including closely related allopatric S. flavicollis and S. ponticus), as well as of the European and Asian races of pygmy wood mouse S. uralensis at the COI gene was demonstrated. However, genetic differences of the Sylvaemus species were 1.5 times and more higher than the distance (D) between the races of S. uralenciis. This finding provides no ample grounds to treat the latter as the independent species. The only specimen of Pamir-Alay subspecies S. uralensis pallipes examined showed closest relatedness to to the Asian race, although was rather distant from it (D = 0.038). No reliable isolation of the eastern European and southern European chromosomal forms, representing the European race of S. uralensis, as well as of their presumptive hybrids from the outskirts of the city of Sal'sk, Rostov region, at the COI gene was revealed. A hybrid origin of the populations of pygmy wood mouse from the outskirts of the Talapker railway station, Novovarshavsky district, Omsk region, was confirmed. In preliminary studies, based on karyotypic characters, these populations were diagnosed as distant hybrids of the eastern European chromosomal form and the Asian race. In yellow-necked wood mouse S. flavicollis from the territory of Russia and Ukraine, weak differentiation into northern and southern lineages (with mean genetic distance between them of 0.020) was observed. Considerably different relative genetic distances between the races of S. uralensis and the S. flavicollis--S. ponticus species pair, inferred from the mitochondrial cytochrome oxidase and cytochrome b gene data, indicated that the rates of evolution of different mitochondrial genome regions could be very different. It is suggested that transformations of the cytochrome b gene, or at least its part, were irregular in time and/or in different phyletic lineages (i.e., accelerated upon the formation of pygmy wood mouse races, and delayed upon the establishment of S. flavicollis and S. ponticus).

Using karyological, allozyme, and molecular genetic analysis, habitation of the four Sylvaemus wood mice species, pygmy wood mouse (S. uralensis), wood mouse (S. sylvaticus), yellow-necked mouse (S. flavicollis), and yellow-bellied mouse (S. fulvipectus) in Rostov oblast was demonstrated. Sylvaemus uralensis was distributed nearly over nearlythe whole territory of the oblast; S. sylvaticus was found in the central and western parts of the oblast on the right bank area of Don River; S. flavicollis inhabited northern and central parts of the right bank area of Don River; S. fulvipectus was found in the southern parts of the oblast, in the left bank area of Don River. Using the chromosome C-banding technique, it was demonstrated that the pygmy wood mice living in Rostov oblast in the right bank areas of Manych River and Don River in its low course, belonged to the eastern European chromosomal form of S. uralensis. The mice from the outskirts of the town of Salsk, the left bank area of Manych River, were probably hybrids between eastern European and southern European chromosomal forms. Based on the mitochondrial DNA cytochrome b gene fragment sequencing and chromosome C-banding, it was suggested that the wood mice inhabiting Rostov oblast belonged to the southern lineage of S. sylvaticus, living on Apennine Peninsula, Balkan Peninsula, and nearly throughout Ukraine.

The results of the epidemiological analysis of the outbreak of hemorrhagic fever which was caused by Crimean-Congo hemorrhagic fever virus and occurred during the period of July 3-19, 1999, in the Oblivskaya district of Rostov Province are presented. The specific epidemiological features of the outbreak have been determined. The possible versions of the appearance of the focus of infection and the role of Ixodes ticks in the circulation of the infective agent are discussed.