Korean Field Mouse Apodemus Peninsulae Research Articles

Phylogeography of Korean field mouse Apodemus peninsulae (Rodentia: Muridae): an update

Abstract To better understand the evolutionary and demographic histories of the Korean field mouse Apodemus peninsulae we examined mitochondrial (mt) cytochrome b gene sequences of 200 specimens from 65 localities in China, Japan, Korea, Mongolia, and Russia. The phylogenetic and phylogeographic analyses revealed three major groups of haplotypes: “Chinese” (C), “Korean” (K) and “Russian” (R). C includes only the samples from southern and central China, K combines all samples from Korean Peninsula and some samples from Siberia, and R comprises all samples from Russian Far East, Japan, and most samples from Siberia. Both R and K also include the samples from Northern China and Mongolia. Coalescent-based approaches suggest a link between separation of these groups and intensive Kung-Huang Pleistocene uplift event of the Tibetan Plateau. The rapid expansion events in R are associated with marine isotope stages (MIS) 3 and 4, and in K with MIS 6; no sings of rapid expansion were found in C. The widespread settlement of the northeast occurred in two waves, close in time: 1) to Northern China and Korean Peninsula, and then 2) to most of Siberia, the Russian Far East and Japan; parts of Siberia, Mongolia and northern China were colonized twice.

Stability of the Population System of B Chromosomes of the Korean Field Mouse Apodemus peninsulae (Mammalia, Rodentia) in the Southern Baikal Region: 35 Years of Observations

Stability of the Population System of B Chromosomes of the Korean Field Mouse Apodemus peninsulae (Mammalia, Rodentia) in the Southern Baikal Region: 35 Years of Observations

The occurrence of dot-like micro B chromosomes in Korean field mice Apodemus peninsulae from the shore of the Teletskoye Lake (Altai Mountains).

The data on the changes in the cytogenetic structure of the geographic population of Korean field mouse Apodemus (Alsomys) peninsulae Thomas, 1907 at the southern shore of the Teletskoye Lake (Altai Republic) are presented. In 1980 no dot-like microchromosomes were found in 34 mice captured on the southern and northern coasts of the Teletskoye Lake. In 2011, a 1.6-fold (from 2.7 to 4.3) increase in the mean number of B chromosomes compared to the rate estimated there earlier in 1980 was discovered. In 11 of the 15 mice (73%) captured in 2011, the karyotypes contained 1–2 dot-like micro B chromosomes and 1–5 macro B chromosomes. The pollution of the territory by the remains of the rocket fuel components may be an appropriate explanation for the cause of the karyological changes observed in A. peninsulae in this region.

Assessment of Developmental Stability during Population Dynamics of the Korean Field Mouse (Apodemus peninsulae) in Mongolia

The development stability has been assessed (by the magnitude of the fluctuating asymmetry of craniological traits) with the change in the number of the Korean field mouse Apodemus peninsulae in Mongolia. It has been shown that an increase in the abundance of this species is not accompanied by a violation of developmental stability, but occurs against the background of a high abundance of other species (the gray red-backed vole Clethrionomys rufocanus and the reed vole Microtus fortis). The result obtained testifies to the assumption that not only the population size of the studied species itself, but also the increase in the number of other species of the community can play a role in manifestation of the overcrowding effect, which can lead to a change in the state of individuals recorded in this case by reduce the developmental stability.

B Chromosome System in the Korean Field Mouse Apodemus peninsulae Thomas 1907 (Rodentia, Muridae).

In this paper, we analyzed B chromosome variation in Korean field mouse Apodemus peninsulae Thomas 1907 (Rodentia, Muridae) based on a 40-year study of karyotypes collected from geographically distant populations in East Siberia, North Mongolia, China, the Russian Far East, and Japan (Hokkaido). We developed the database of individual variants of B chromosome systems in A. peninsulae. In Siberian populations all animals had Bs. The karyotypes of the studied animals contain from 1 to 30 Вs differing in size and morphology. Analysis of B chromosome systems in 598 individuals from different localities of the range shows the presence of 286 variants of Вs combinations in these animals. Unique sets of B morphotypes make up most of these variants (64.7 ± 1.3%), probably suggesting that individual Bs systems normally result from stochastic processes in the populations. The proportion of animals with a large number of Bs gradually decreases, probably due to increased complexities in the inheritance of large numbers of Bs. A. peninsulae is thus proposed as a good model for studying the origin and evolution of extra elements in the karyotype.

Replication of RNA of Tick-Borne Encephalitis Virus in New Transferable Cell Lines of the Natural Host Apodemus peninsulae

Cell lines derived from natural virus hosts are one of the most promising tools in virological research. The aim of this work is to establish the dynamics of RNA replication of tick-borne encephalitis virus (TBEV) in new transferable cell line of kidney of the Korean field mouse Apodemus peninsulae (ApnK) and compare it with replication in the traditional culture of fetal porcine kidney cells (SPEVs). The transplantable ApnK cell line was obtained in the laboratory of transmissive infections of the Scientific Center for Family Health and Human Reproduction Problems (Irkutsk), the identity of the culture was established by the analysis of nucleotide sequence of mitochondrial cytochrome B gene (mtCytB, GenBank access number KT983422), and the D-loop sequence of the mitochondrial genome (KT983423). Cells were inoculated with TBEV strain of the Siberian subtype 92M and the total RNA was isolated from them 0, 4, 8, 16, and 24 h after infection. In addition, RNA was also isolated 1, 4, 7, and 19 days after infection. The amount of intracellular RNA of the positive polarity (+RNA) was assessed by quantitative real-time PCR. At the initial stage of infection (0 h after infection) in ApnK cells, the intracellular +RNA concentration was significantly lower than in SPEV, 4.5 lg versus 5.5 lg of genome-equivalents/μL (p = 0.01). After 8 h, in ApnK cells there were no significant difference with points 0 and 4 (p = 0.5 and p = 0.1, respectively), whereas in SPEV at this stage the concentration of RNA was significantly higher than at points 0 and 4 (p = 0.001 and 0.01, respectively). In general, during the first day of infection, the concentration of +RNA in ApnK cells was almost ten times less than in SPEV (p = 0.001). By the fourth day after infection, ApnK cells showed maximum concentrations of +RNA, 7.8 lg of genome-equivalents/μL, with no differences with SPEV (p = 0.06). Subsequently, the amount of RNA in ApnK cells remained at the same level for 19 days, and in SPEV in late terms there was a tendency to decrease in the concentration of +RNA. The results obtained suggest that TBEV in A. peninsulae has an intracellular mechanism for controlling viral infection, which acts both at the stage of the entrance of virion into the cell and by regulating the rate of synthesis of genomic and/or replicative forms of viral RNA.

Features of the B chromosome in Korean field mouse Apodemus peninsulae (Thomas, 1906) from Transbaikalia and the Far East identified by the FISH method

Korean field mice (Apodemus peninsulae) are widely distributed throughout northeastern Asia, including the Russian Far East, northern China, the Korean peninsula, Sakhalin, and Hokkaido. This mouse species is characterized by a high frequency of animals with B chromosomes differing in their number, morphology, and DNA composition in different geographical regions. For the first time a comparative analysis of DNA probes from B chromosomes with metaphase chromosomes of mice from Transbaikalia, the Far East (including the Russian Far East), Japan, and South Korea was conducted by in situ hybridization. B chromosomes in mice from the Russian Far East were shown to exhibit low variability in DNA content; however, the DNA composition of B chromosomes in species from Transbaikalia and Japan were highly variable. B chromosomes in A. peninsulae from the South Korean population demonstrate minor differences from those from the Russian Far East. We discuss the origin of B chromosomes in the studied region in comparison with previously obtained data for mice from Siberia and the Baikal region, as well as the dispersal routes of the Korean field mouse.

The mitochondrial genome of Apodemus peninsulae (Rodentia, Muridae)

The complete mitochondrial (mt) genome of the Korean field mouse Apodemus peninsulae was sequenced and found to be 16,266 bp in length. The mt protein-coding genes of A. peninsulae had ATG, GTG, ATC, and ATA as initiation codons and TAA, TAG, TA, and T as termination codons. Two forms each of trnL and trnS and the three tRNA clusters, IQM, WANCY, and HSL were identified, as in the typical Rodentia mt genome. Among tRNAs, abnormal cloverleaf structure of trnS(AGY) was identified in DHU arm. The l-strand replication origin has the potential to form a stable stem–loop structure and control region has several conserved sequence elements.

Polymorphism and mosaicism of B chromosome number in Korean field mouse Apodemus peninsulae (Rodentia) in the Russian Far East

A karyotype analysis of the Apodemus peninsulae (n = 355) from 41 trapping points from the Russian Far East has allowed us to identify B chromosomes in 87.9% of the animals, 61.7% of which are mosaics. Different levels of variability in the B chromosome numbers have been studied, including both the inter- and intrapopulational, as well as intraindividual variability (mosaicism). It was found that the frequencies of the occurrence of individuals with B chromosomes and mosaicism between different population samples were not constant. The range of the modal B chromosome number variability and variation of the xB index (zero to four; on average, the xB amounted to 1.67) were studied for the first time in different samples and populations of this species. Individuals with the predominant numbers of B chromosome (as a rule, zero to two) were revealed in both groups of animals (with stable and mosaic karyotypes), but the frequency was different in geographical regions. The spectra of B chromosome variability were wider in mosaics (zero to seven) compared to animals with stable karyotypes (zero to four). The importance of this for species of the high frequency of individuals with B chromosomes and with mosaicism has been discussed. The adaptive role of the low number of B chromosomes (one to two), as well as the imbalance of the B chromosome system for the species as a whole is assumed.

Body temperature profiles of the Korean field mouse Apodemus peninsulae during winter aggregation

ABSTRACT Factors affecting body temperature (Tb) fluctuations in winter were examined in Korean field mice Apodemus peninsulae. Animals were maintained under the following three conditions to mimic autumn followed by winter, plus two modes of behaviour, solitary and grouped, in winter: 1) short day (8 Light:16 Dark) at 25 ± 2°C and solitary, for 12 weeks towards the end of which their Tb was recorded; 2) constant darkness (DD) at 4 ± 2°C and solitary, for a week; and 3) DD at 4 ± 2°C and in groups (two or three animals in a cage), for about 10 days. Using implanted data loggers Tb was monitored in 13 mice that were exposed to these three conditions in sequence. When the animals' body temperature was below 30°C, it was assumed that they were torpid according to the bimodal pattern of minimum daily Tb. The maximum period of daily torpor was 390 min/day, and torpor was exhibited by seven of the thirteen animals exposed to conditions-2) and -3). Since torpor was found in one mouse even under condition-1), wit...

Comparative analysis of micro and macro B chromosomes in the Korean field mouse Apodemus peninsulae (Rodentia, Murinae) performed by chromosome microdissection and FISH

Comparative analysis of micro B and macro B chromosomes of the Korean field mouse Apodemus peninsulae, collected in populations from Siberia and the Russian Far East, was performed with Giemsa, DAPI, Ag-NOR staining and chromosome painting with whole and partial chromosome probes generated by microdissection and DOP-PCR. DNA composition of micro B chromosomes was different from that of macro B chromosomes. All analyzed micro B chromosomes contained clusters of DNA repeats associated with regions characterized by an uncondensed state in mitosis. Giemsa and DAPI staining did not reveal these regions. Their presence in micro B chromosomes led to their special morphology and underestimation in size. DNA repeat clusters homologous to DNA of micro B chromosome arms were also revealed in telomeric regions of some macro B chromosomes of specimens captured in Siberian regions. Neither active NORs nor clusters of ribosomal DNA were found in the uncondensed regions of micro B chromosomes. Possible evolutionary pathways for the origin of macro and micro B chromosomes are discussed.   

B chromosomes of Korean field mouse Apodemus peninsulae (Rodentia, Murinae) analysed by microdissection and FISH

Organization of B chromosomes in the Korean field mouse Apodemus peninsulae was analyzed. We painted its metaphase chromosomes with whole and partial chromosome paints generated by microdissection and DOP-PCR. The results of the painting indicated that all B chromosomes contained a large amount of repeated DNA sequences. The repeats could be classified in terms of their homology and predominant location. Pericentromeric repeats of B chromosomes were present in many copies in pericentromeric C-blocks of all autosomes and in non-centromeric C-blocks of the sex chromosomes. B arm specific type 1 repeats comprised the main body of the arms of almost all B chromosomes and were present in the arms of A chromosomes as interspersed sequences. B arm-specific type 2 repeats were found at the ends of some B chromosomes that did not undergo compaction at the interphase– metaphase transition and remained uncondensed. On the basis of comparative analysis of localization of B chromosome repeats in the chromosomes of two related species, A. peninsulae and A. agrarius, we suggest a hypothesis of B chromosome origin and evolution in the genus Apodemus.