Features of Interspecific Contacts and Hybridization of Ground Squirrels (Marmotinae, Sciuridae, Rodentia) in Mongolia.

Using molecular genetic methods, we investigated the secondary contact zones of two pairs of species of ground squirrels of Mongolia. In common colonies of marmots M. sibirica and M. baibacina, we revealed a high frequency of occurrence of hybrid individuals that were viable and fertile. A hybridization between S. alaschanicus and S. pallidicauda was sporadic in nature. The hypothesis about an extensive hybrid zone in these species of ground squirrels was not confirmed. An occupation of suboptimal biotopes by individuals of different species was the main factor contributing to hybridization in both case. The complex social behavior in marmots affected on the localization and diffusion of the hybridization process.

[Phylogeny of genus Spermophilus and position of Alashan ground squirrel (Spermophilus alashanicus, Buchner, 1888) on phylogenetic tree of Paleartic short-tailed ground squirrels].

Phylogenetic relationships within a group of Paleartic short tailed ground squirrels (Spermophilus), recently defined as genus, are not sufficiently clear and need a critical revision. Interspecies hybridization, found in Eurasian Spermophilus, can affect the results of reconstruction of molecular phylogeny. Alashan ground squirrel position on the phylogenetic tree needs clarification. We analyzed eight nucleotide sequences of cytb gene of S. alashanicus and 127 sequences of other Spermophilus species form GenBank. S.alashanicus and S. dauricus close phylogenetic relationship, and their affinity to ancestral forms of the group are revealed. Monophyly of Colobotis subgenus was confirmed. Paraphyly of eastern and western forms of S. relictus was shown.

[Spatial distribution of Marmota baibacina and M. sibirica (Marmota, Sciuridae, Rodentia) in a zone of sympatry in Mongolian Altai: bioacoustic analysis].

The spatial distribution of two marmot species Marmota baibacina and M. sibirica in a zone of coexistence was studied by using their alarm call as a diagnostic trait. It was found that M. baibacina prefers to inhabit bouldery screes, whereas M. sibirica inhabits all suitable biotopes. The difference in biotopic distribution of these species could be explained by M. sibirica forcing M. baibacina out of optimum habitats. Cases of coexistence of both species in one family group sites were registered, which might contribute to the appearance of hybrids.

[Phylogeny and systematics of marmots inferred from inter-SINE PCR data].

Phylogenetic and taxonomic relationships in the genus Marmota were examined using inter-SINE PCR. The primers used were complementary to the consensus sequences of two short retroposons, MIR and B1-dID. The results suggest long-term genetic isolation of Nearctic and Palearctic marmots, but do not support subgeneric subdivision because of relatively low genetic differences between the marmot groups. Confirmation was received for the isolation of bobak and camtschatica, but not the caudata intrageneric species groups. Based on comparison of the mitochondrial and nuclear genome differences, the possibility of ancient hybridization between M. menzbieri and M. caudata was recognized. Species independence of M kastschenkoi within the suggested superspecies of M. baibacina was supported.

[Genetic connections and differentiation of ground squirrels Marmotinae Pocock, 1923 (Rodentia, Sciuridae) from Palearctics]. / Geneticheskie sviazi i differentsiatsiia nazemnykh belich'ikh Marmotinae Pocock, 1923 (Rodentia, Sciuridae) palearktiki.

Genetic distances between eight species of sousliks (Spermophilus) and five species of marmots (Marmota) were estimated on the basis of 39 biochemical loci. All taxa were shown to be genetically discrete. The genetic differentiation was minimal (Pfd = 11.3) between parapatric species of Palearctic sousliks of the suslicus pigmaeus group and Marmota species, intermediate (Pfd = 34.7) between allopatric sousliks species, and maximal (Pfd = 56.7) between representatives of different genera. The following trends were revealed in the geographic differentiation of the genus Spermophilus: (1) genetic similarity was associated with the geographic distance; (2) the eastern and western Palearctic phyla were markedly different genetically; (3) the eastern Palearctic forms exhibited higher differentiation than the western ones. The revealed speciation pattern is consistent with the general trend of temporal differentiation in Palearctic phyla and confirms the periodic speciation mode in the Palearctics.

[Allozyme differentiation of various chromosomal forms of the spotted suslik (Spermophilus suslicus Guld, 1770, Rodentia)]. / Allozimnaia differenttsiatsiia raznokhromosomnykh form krapchatogo suslika (Spermophilus suslicus Guld, 1770, Rodentia).

Eleven enzyme and four nonenzyme protein systems controlled by 25 loci were electrophoretically analyzed in the allopatric karyotypic forms (2n = 34 and 2n = 36) of the spotted souslik Spermophilus suslicus. Genetic variability and differentiation for the forms with different chromosome sets were estimated. Two discriminative loci (Alb and Tf) for the studied chromosome forms were found. The UPGMA dendrogram was constructed, which summarizes genetic (allozyme) relationships found for the forms of the spotted souslik with different chromosome sets. Subdividing the species into two karyotypic forms was shown to be followed by differentiating these forms at the allozyme level.