Karyotype Evolution and Phylogenetic Relationships of <b><i>Cricetulus sokolovi</i></b> Orlov et Malygin 1988 (Cricetidae, Rodentia) Inferred from Chromosomal Painting and Molecular Data

Abstract

Sokolov's dwarf hamster (Cricetulus sokolovi) is the least studied representative of the striped hamsters (Cricetulus barabensis species group), the taxonomy of which remains controversial. The species was described based on chromosome morphology, but neither the details of the karyotype nor the phylogenetic relationships with other Cricetulus are known. In the present study, the karyotype of C. sokolovi was examined using cross-species chromosome painting. Molecular and cytogenetic data were employed to determine the phylogenetic position of Sokolov's hamster and to analyze the potential pathways of chromosome evolution in Cricetulus. Both the chromosome and molecular data support the species status of Sokolov's hamster. Phylogenetic analysis of the CYTB data placed C. sokolovi as sister to all other striped hamsters (sequence divergence of 8.1%). FISH data revealed that the karyotype of C. sokolovi is highly rearranged, with the most parsimonious scenario of its origin implying at least 4 robertsonian events and a centromere shift. Comparative cytogenetic data on Cricetinae suggest that their evolutionary history includes both periods of chromosomal conservatism and episodes of rapid chromosomal change.

Phylogeographic structure in the chromosomally polymorphic rodentCricetulus barabensissensu lato (Mammalia, Cricetidae)

“…This prediction is primarily consistent with the range of values observed between pairs of sibling species of Palearctic hamsters. The distance between C. barabensis and C. sokolovi (~8%) suggests species‐level differentiation (Poplavskaya, Romanenko, et al., ). Considering other genera, the level of divergence between Mesocricetus newtoni and M. brandti is 9%; between M. auratus and M. raddei , 6%; and between Phodopus sungorus and Ph.…”

“…This implies that the “griseus” and “barabensis” karyotypes are derived from 2 n = 24 by two centric fusions. However, FISH‐based ancestral reconstructions (Poplavskaya, Romanenko, et al., ) suggested that the MAU2/7 association was present in ancestral karyotypes of the genus Cricetulus and C. barabensis sensu lato + C. sokolovi clade. The topology of the mitochondrial tree is most consistent with the scenario implying the 2 n = 20 (“barabensis”) ancestral karyotype.…”

“…One can hypothesize that this species originated in some southerly refugium in Gobi, where it was locked during one of the arid phases of Pleistocene climatic oscillations. A refugial bottleneck may explain the fact that the karyotype of C. sokolovi is highly rearranged relative to other Cricetulus (Poplavskaya, Romanenko, et al., ).…”

“…In addition to C. barabensis s. l., the species group also includes the Gobi hamster Cricetulus sokolovi , Orlov and Malygin, , which was originally described as a full species based on distinct karyotype morphology (Orlov et al., ; Orlov & Malygin, ). Although C. sokolovi is closely related to C. barabensis , its full species rank has now received decisive support from molecular and chromosome staining data (Poplavskaya, Romanenko, et al., ).…”

“Noah’s Ark” Project: Interim Results and Outlook for Classic Collection Development

“…The combination of genomic phylogeography and genetic barcoding provided new data on the structure of species diversity in a number of animal groups. In the Nothybidae (Insecta) family [78], several economically important species of Salmonidae and Cyprinidae (Osteichthyes) [79][80][81][82][83][84] and species-level taxa from 10 families of terrestrial vertebrates in Eurasia have been studied in this respect [64,[85][86][87][88][89][90][91][92][93][94][95]. The high efficiency of COI gene analysis in revealing the diversity of phylogenetic lineages in a number of Amphibia genera has been demonstrated [96].…”