Winter Reproduction of Cyclomorphic Mammals: From a Case to the Phenomenon.

In 2010 (a year of drought), the true winter breeding (TWB) of the pygmy wood mouse (S. uralensis) was first recorded in the Southern Urals and confirmed by the morphological parameters and age markers. The young born in winter fulfilled successfully their reproductive potential under favorable climatic conditions. The true winter breeding and the age cross of animals during the year of drought promoted the maximum population growth and enhanced population genetic heterogeneity. In subsequent years, TWB of S. uralensis became common, which is regarded as a climatic pattern. Extreme drought rearranged the rodent community and caused TWB of S. uralensis, which resulted in a higher abundance of the species.

[Analysis of Microsatellite DNA in Rodents from Eastern Urals Radioactive Trace Zone and Contiguous Territories].

The variability of four microsatellite loci of rodents, caught from the head part of Eastern Urals Radioactive Trace (EURT), along with the rodents inhabiting contiguous zone with background radiation level and distant-reference territory, was analyzed forthe first time. Differences in the parameters of genetic diversity between northern red-backed voles from the EURT zone and from the reference population were detected. An increase in some indices of genetic diversity in animals from a contiguous to the EURT zone was found; this is probably associated with animal migration and configuration of the area of pollution. A transfer of radiation-induced effects to the contiguous territories and a decrease in the possibility of fixation of adaptations in a series of generations of mobile rodent species in the area of local radioactive pollution are consequences of migrations. The results of the study make it possible to recommend microsatellite markers for the analysis of radiation-induced effects in rodents as model objects of radioecological monitoring.

[Role of polyalternativeness of animals' ontogeny development in the estimation of ionizing radiation consequences].

The role of polyalternativeness of small mammals' ontogeny development (belongings of individuals to alternative pathways of the ontogeny development) in the estimation of effects of ionizing radiation is considered. It is shown that biological consequences of acute (laboratory experiment) and chronic (inhabiting the Eastern Urals Radioactive Trace zone) ionizing radiation in rodents significantly depend on the belonging of individuals to the pathway of ontogeny. Specificity of the response of the population to acute and chronic irradiation is revealed. It is concluded that it is necessary to take into account the belonging of individuals to the pathway of ontogeny development in a wide spectrum of investigations at the analysis of any biological parameters in small rodents in the zones of local technogenic contamination.

[Migration of rodents in the Eastern Urals Radioactive Trace zone (radiobiological aspect)].

We investigated migrations of mouse-like rodents in the Eastern Urals Radioactive Trace (EURT) zone using the method of small mammal group marking by tetracycline (additionally to the data of radionuclide self-marking). The originality of small mammals' population in the EURT zone is defined by a configuration of radioactively polluted area and features of animals' migrations. The tetracycline label is detected in the dentine of upper incisors fluorescing in UV light. A high migration activity of rodents is observed both in the EURT zone and adjacent areas. When migrating, rodents used the certain ways of moving. Our new data allowed us to conclude that the EURT zone, as well as any other areas, is inhabited by a population with a constantly changing set of individuals, i.e. a flowing population. It is the convincing evidence of the absence of any isolation. Migrations of small mammals in the narrow and extended EURT zone (1) considerably decrease the probability that certain adaptive changes may be fixed and inherited in a series of generations; (2) are the base of transmission of radio-induced effects in adjacent areas. The fact of a flowing population should be taken into account in a wide spectrum of investigations when analyzing the remote consequences of chronic radiation influence.