Fluctuations in the Rate of Radioactive Decay of the Natural Potassium-40 Isotope Can Potentially Affect the Periodic "Spontaneous" Activity of Animals.

Body temperature rhythms of C57Bl/6 laboratory mice and common greenfinches (Chloris chloris) and feeding periods of common starlings (Sturnus vulgaris) were compared with the intensity of fluctuations in 40К radioactive decay. Body temperature changes in greenfinches and mice were found to positively correlate with the intensity of fluctuations in 40K radioactive decay. Superposed epoch analysis showed that an increase in mouse body temperature, which reflects the start of the active phase in the sleep-wake cycle, and food intake in starlings coincide with an increase in the intensity of 40K radioactive decay. Thus, animal activity in the ultradian range of periods may be related to external quasi-rhythmic physical influences, rather than being determined only by endogenous processes. Given the extremely low dose of natural 40К exposure, a factor responsible for radioactivity fluctuations may act as a biotropic factor.

Phylogeny of the Dipus sagitta Species Complex by Nuclear Gene Sequences.

The northern three-toed jerboa Dipus sagitta had long been considered to be a single polytypic species. High genetic diversity of D. sagitta was earlier revealed on the basis of several mitochondrial and nuclear genes, and several separate species were hypothesized to occur within the taxon. However, the relationships between phylogenetic lineages have not been established because of the small sample size of nuclear genes. In the present work, a far larger set of nuclear DNA loci was used, and thus, a higher resolution of the phylogenetic tree was achieved for ten D. sagitta forms. The structure revealed for the species mainly confirmed the topology and relationships of the mtDNA lineages. Yet the mitochondrial and nuclear phylogenies were not completely consistent. Some of the D. sagitta genetic lineages were therefore assumed to be a product of reticular evolutionary processes. The taxon was concluded to be the diverse species complex D. sagitta sensu lato, in which long-diverged lineages are not always reproductively isolated.

Ultradian Near 2-4-h Rhythms of Body Temperature in Laboratory Rodents Depend on External Environmental Heliogeophysical Factor Reflected by Neutron Monitor Count Rate.

The study collated oscillations of body temperature of С57BL/6 mice and Roborovski hamsters (Phodopus roborovskii) in the period range of 100-240 min and fluctuations of the secondary cosmic rays reflected by neutron count rate of a neutron monitor at the Earth's surface. Cross-correlation of body temperature and neutron count rate data revealed their strong association only for simultaneous measurements. Collation of the phase of neutron count rate fluctuations with maxima of body temperature oscillations revealed the coincidence of the phases of both processes. There was a temporary connection between the periods of body temperature elevation and neutron count rate rise. Thus, not only the spectral parameters of biological and physical processes, but also their phases coincided, which corroborates the hypothesis on stimulating effect of increasing neutron count rate on activity of the animals.

Association between Rhythmic Variations of Mouse Body Temperature with 4-16-Minute Periods and Geomagnetic Undulations in Corresponding Frequency Range Pc5/Pi3.

The rhythmic variations of body temperature in two groups of mice located in Moscow and Novosibirsk were compared with geomagnetic undulations within Pc5/Pi3 (1-5 mHz) range measured in Borok and Novosibirsk middle-latitude geophysical observatories located at the same longitudes as the examined mice. The spectral maxima of geomagnetic undulations and body temperature variations were observed with greatest probability at the frequencies of 1.6, 2.3, and 3.1 mHz. At this, the mean square of the distance between the frequencies of spectral maxima of simultaneous oscillations was smaller than that of random intervals favoring the hypothesis on geomagnetic undulations as the synchronizer of biorhythms. In both groups of mice, the share of intervals with a high spectral coherency between geomagnetic undulations and body temperature variations had common maximum in the pre-midnight sector of local time and it was higher for the large-scale geomagnetic undulations. Dependence of geomagnetic undulations on spatial scale suggests that body temperature is affected by electrotelluric field.

Ultradian Rhythms of Body Temperature Are Associated with Temperament in Greenfinch (Chloris chloris, Fringillidae, Aves).

Previously, in male Greenfinch, we have described ultradian rhythms of body temperature with periods of 3-6, 8-10, 12-20, and 40-60 min. There are individual variations in this rhythmicity. Rhythms with a period of 3-7 min are more characteristic of some males but not for the others. These males had small values of the ratio of the harmonic spectral density in the range of 12-20 min to the harmonic spectral density in the range of 3-7 min. In this study, we hypothesized that ultradian rhythmicity of body temperature fluctuations is related to the nervous system activity in general and to temperament in particular. We have conducted two sets of experiments for estimating the aggression level (n = 12 males) and reaction to novelty (n = 17). Individuals with predominant rhythms with a period of 3-7 min are less aggressive and more slowly adapt to new conditions. Thus, the ultradian body temperature rhythmicity in Greenfinch is related to their behavioral features and temperament.

Is the Periodic "Spontaneous" Activity of Animals Determined by a Quasi-Rhythmic Factor of the External Environment?

We have studied the dynamics of the singing of garden bunting (Emberiza hortulana) and the dispersal of a flock of starlings (Sturnus vulgaris) for the night rest. The results were compared with the body temperature fluctuations measured in parallel in a group of laboratory mice. The validity of such comparisons was determined by the presence of a stable correlation between the indicators of minutely changes in body temperature in mice and greenfinches (Chloris chloris). The increase in the frequency of chanting of garden buntings was observed simultaneously with the increase in body temperature in mice. Moreover, the exact moments of the flights into the birdhouse for the night in starlings coincided with the maximums in the dynamics of minutely changes in body temperature of mice. These facts suggest an external synchronizer of "spontaneous" fluctuations of the activity and associated changes in body temperature, which are probably determined by the tone of the sympathetic nervous system.

Circahoralian Rhythms of Body Temperature in Mammals and Birds with Different Metabolism Levels.

The time course of intraperitoneal body temperature has been analyzed in two species of mammals (laboratory C57Bl/6 mice and white-breasted hedgehogs (Erinaceus roumanicus) and in two species of passerine birds (common greenfinch Chloris chloris and Japanese quail Coturnix japonica) with different body weights. Similar sets of basic harmonics appearing synchronously in different individuals have been found in the body temperature spectra of the species studied. The level of basal metabolism in those animal species considerably vary; therefore, the period of fluctuations of body temperature in the range of 10-120 min is not determined by the internal characteristics of the body and, presumably, reflects the influence of an external biotropic environmental factor.

The Phenomenon of Synchronous Food Intake in Starlings (Sturnus vulgaris) under the Conditions of Isolation from Each Other.

The dynamics of body temperature was used to determine the food intake synchronization in starlings located at a distance of 105 km from each other. Thermal accumulators were implanted intraperitoneally to the birds; the birds had free access to food or were kept under the conditions of food deprivation. It was found that food intake moments significantly more often coincided with an accuracy of up to a minute even in the birds separated by a considerable distance. The difference in time of sunrise of a few minutes, as well as the conditions of constant lighting did not affect the synchronism of food intake. On the basis of the data obtained, it can be assumed that there is a certain external factor, probably of an electromagnetic nature, which synchronizes the functional activity of the body, including food intake.

Is the Center of Origin of Long-tailed Hamster Cricetulus longicaudatus Milne-Edwards 1867 (Rodentia, Cricetidae) Located in Tibet?

First data on morphological and mitochondrial variation in the long-tailed hamster Cricetulus longicaudatus is presented. In contrast to genetically monomorphic populations of Mongolia and Tuva, the northeastern part of the Qinghai-Tibetian Plateau was found to harbor several divergent mtDNA lineages. This pattern suggests a recent expansion of the long-tailed hamster to the northern part of its recent range, which started from Tibet, presumably, in the late Middle Pleistocene. Several populations from the northern edge of the species range were found to be morphologically but not genetically distinct. The apparent disagreement between genetic and morphological data can be explained by rapid morphological evolution in peripheral isolates.

Molecular phylogenetics and taxonomy of dwarf hamsters Cricetulus Milne-Edwards, 1867 (Cricetidae, Rodentia): description of a new genus and reinstatement of another.

The taxonomy of the genus Cricetulus has been controversial. The phylogenetic relationships both within the genus and among Cricetulus lineages and other genera were examined using a set of five nuclear and two mitochondrial genes. The results demonstrate that Cricetulus in its current treatment is a polyphyletic assemblage because the subgenus Urocricetus is phylogenetically unrelated to all other Cricetulus and is a distant sister group to Phodopus. The grey hamster (C. migratorius) proved to be closer to Cricetus and Allocricetulus than to Cricetulus proper, which includes C. barabensis C. sokolovi and C. longicaudatus. Based on these results Urocricetus is elevated to the rank of a full genus and a new genus Nothocricetulus gen.nov. is described for the grey hamster.

[Microsatellite loci variation and investigation of gene flow between two karyoforms of Cricetulus barabensis sensu lato (Rodentia, Cricetidae)].

We examine the diversity of six microsatellite loci and partial RAG1 exon of "barabensis" and "pseudogriseus" karyoforms in Cricetulus barabensis sensu lato species complex. A total of 435 specimens from 68 localities ranging from Altai to the Far East are investigated. The results of the population structure analysis (factor analysis and NJ tree based on Nei genetic distances) support subdivision into two well-differentiated clusters corresponding to the two karyoforms. These karyoforms are also well differentiated by the level of microsatellite variability. In several "barabensis" specimens, we found microsatellite alleles that are common in "pseudogriseus" populations but are otherwise absent in "barabensis." Most of these specimens originate from a single population in one of the zones of potential contact between karyoforms, Kharkhorin in Central Mongolia. These molecular results are consistent with previously published karyological data in suggesting that rare hybridization events between the two chromosomal races occur in nature.

[Genetic Structure of Urban Population of the Common Hamster (Cricetus cricetus)].

Over the past half-century, the common hamster (Cricetus cricetus), along with range-wide decline of natural populations, has actively populated the cities. The study of the genetic structure of urban populations of common hamster may shed light on features of the habitation of this species in urban landscapes. This article is focused on the genetic structure of common hamster populations in Simferopol (Crimea), one of the largest known urban populations of this species. On the basis of the analysis of nucleotide sequences of the cytochrome b gene and mtDNA control region, and the allelic composition of ten microsatellite loci of nDNA, we revealed that, despite the fact that some individuals can move throughout the city at considerable distances, the entire population of the city is represented by separate demes confined to different areas. These demes are characterized by a high degree of the genetic isolation and reduced genetic diversity compared to that found for the city as a whole.

Seasonal Changes in Blood Cells and Biochemical Parameters in the Mongolian Hamster (Allocricetulus curtatus).

It was shown previously that the Mongolian hamster (Allocricetulus curtatus) is a mammalian species with irregular short hibernation. The purpose of the present study was to determine how this status affects seasonal changes in the biochemical and hematological parameters in A. curtatus males under a natural temperature and light regime. It was found that a reduction in circulating white blood cells, specifically lymphocytes, neutrophils, eosinophils, basophils, and monocytes, occurred in-winter. and bilirubin levels increased in spring. These characteristics make Mongolian hamsters closer to the true hibernating species. At the same time, the character of seasonal changes in the number of red blood cells, glucose, total protein, creatinine, and albumin is closer to species with torpor.

Comparative cytogenetics of hamsters of the genus Allocricetulus argyropulo 1932 (Cricetidae, Rodentia).

Chromosome painting and G-banding analyses were used to delimit homologous chromosomal segments among 4 taxa of the hamsters genus Allocricetulus Argyropulo 1932 (Cricetidae, Murоidea, Rodentia)--A. curtatus (2n = 20), A. eversmanni eversmanni, A. eversmanni pseudocurtatus, and the hybrid A. eversmanni beljaevi × A. eversmanni pseudocurtatus (all 2n = 26). Comparative maps between the 4 karyotypes were established based on chromosome painting of chromosome-specific probes from the Syrian hamster (Mesocricetus auratus, 2n = 44). A putative ancestral karyotype for the genus Allocricetulus (AAK) was proposed and contains 12-13 ancestral autosomal elements. Integrated maps demonstrate extended conservation of syntenies within this rodent genus and show the predominant role of Robertsonian rearrangements in the karyotype evolution of the genus Allocricetulus. At the cytogenetic level, we clearly demonstrate karyological differences between karyotypes of species (A. curtatus vs. A. eversmanni) and subspecies A. e. eversmanni and A. e. beljaevi versus A. e. pseudocurtatus, but the karyotypes of A. e. eversmanni and A. e. beljaevi are identical at this level of resolution.

[Karyotypes divergence in superspecies complex Cricetulus barabensis sensu lato and their interrelationships in natural contact zones].

Interrelationships between three chromosomal forms of striped hamsters belonging to the superspecies complex Cricetulus barabensis sensu lato (Cricetidae, Rodentia), namely 'barabensis', 'pseudogriseus', and 'griseus', are examined from the standpoint of different biological/genetic species concepts. Craniometric data suggest that differences between the karyotypes are rather of subspecies level. Cytogenetic differences between the karyotypes are also not great and correspond to the level of chromosomal races within a single species. The analysis of mitochondrial gene for cytochrome b (cytb) indicates the level of differences between forms of about 2.3-4.1%. Such a level may correspond to intraspecific differences as well as to differences between allied species. Experiments on hybridization resulted in hybrid litters obtained in different mating combinations of karyotypes. Both hybrid males and females fertility was confirmed, too. In nature, there exist several zones where contact between karyotypes 'barabensis' and 'pseudogriseus' is possible. Within one of such zones, in Central Mongolia, two males with atypical karyotype were detected by use of chromosome analysis. With chromosomes number and form, this karyotype may correspond to the hybrid between second and subsequent generations. However, typing of gene cytb and the intron localized in Y-chromosome (DBY1) did not reveal any traces of recent or ancient hybridization. In the other zone where contact between the karyotypes is possible, in South Buryatia, 'barabensis' and 'pseudogriseus' populations are separated by the River Chika and the distance between them does not exceed 5 km. Nevertheless, no hamsters with non-standard karyotypes and no traces of gene flow are detected by karyological and molecular analyses of these populations. The results of Tajima's test, analysis of pairwise differences distribution and indices of nucleotide diversity obtained in the course of examining gene cytb full nucleotide sequence all suggest that both contact zones studied have formed long ago and the absence of gene flow cannot be explained by their forming in the recent past. Thus, the karyotypes studied appear to be evolutionary lines developing independently from each other.

Karyotype reorganisation in the subtilis group of birch mice (Rodentia, Dipodidae, Sicista): unexpected taxonomic diversity within a limited distribution.

Conventional cytogenetic studies of Sicista subtilis and S. severtzovi (Dipodidae, Sicistinae), both attributable to the subtilis group of birch mice, revealed extensive karyotype diversity with 2n = 16-26 and NFa values of 26-46 indicating the overwhelming non-Robertsonian nature of chromosomal reorganization in these species. The numerical and structural chromosome variability was principally found in specimens located within a confined region of the East European (Russian) Plain. The approximately 135,000-km(2) area occurs in the vicinity of the Don River bend between 49°13'N/43°46'E and 51°32'N/36°16'E. The detection of cytotypes sharing similar 2n and NF values, but having morphologically distinct chromosomes, suggests that these may result from polymorphisms present both within recognized species and in cryptic taxa not hitherto described. We conducted a comprehensive, comparative chromosome banding analysis of 52 birch mice (21 localities) referable to the subtilis group and report the presence of 5 distinct karyotypes, each characterized by a combination of stable, variable, and partly overlapping 2n/NFa values. These karyotypes differed from each other by 10-29 structural chromosomal rearrangements (18.1 ± 6.3) that comprised Rb fusions/fissions (42.2%), pericentric inversions (31.1%), and tandem translocations (22.2%). The composition, and the high numbers of these chromosomal changes, is likely to provide an effective means of post-mating isolation, suggesting that taxonomic diversity within the subtilis group is larger than currently accepted. Additionally, we report the frequent fixation of tandem translocations in sample populations, one of which was found in a polymorphic state representing, as far as we are aware, the first case of an in statu nascendi tandem fusion in wild populations. Moreover, our data revealed that bi-armed chromosomes were involved in fusions detected in some of the subtilis taxa. In each instance, however, fusions were preceded by pericentric inversions that transform one or both bi-armed chromosomes into acrocentrics resulting in either centromere-telomere or Robertsonian translocations. Finally, a phylogenetic scenario inferred from a cladistic analysis of the chromosomal data suggests that the extensive karyotypic diversification within the subtilis group in the south-east region of the Russian Plain most likely results from fragmentation of a continuously distributed, ancestral population. It is thought that this occurred at the last glacial maximum (18,000-14,000 years B.P.), and that the process of isolation has been exacerbated by increasing human activity in the region in modern times.