Chromosomal evolution of Arvicolinae (Cricetidae, Rodentia). III. Karyotype relationships of ten Microtus species

Abstract

The genus Microtus consists of 65 extant species, making it one of the rodentia genera with the highest number of species. The extreme karyotype diversification in Microtus has made them an ideal species group for comparative cytogenetics and cytotaxonomy. Conventional comparative cytogenetic studies in Microtus have been based mainly on chromosomal banding patterns; the number of Microtus species examined by molecular cytogenetics-cross-species chromosome painting-is limited. In this study, we used whole chromosome painting probes of the field vole Microtus agrestis to detect regions of homology in the karyotypes of eight Microtus species. For almost all investigated species, species-specific associations of conserved chromosomal segments were revealed. Analysis of data obtained here and previously published data allowed us to propose that the ancestral Microtus species had a 2n = 54 karyotype, including two associations of field vole chromosomal segments (MAG 1/17 and 2/8). Further mapping of the chromosome rearrangements onto a molecular phylogenetic tree allows the reconstruction of a karyotype evolution pathway in the Microtus genus.

A Comparative Analysis of the Mole Vole Sibling Species <i>Ellobius tancrei</i> and <i>E. talpinus</i> (Cricetidae, Rodentia) through Chromosome Painting and Examination of Synaptonemal Complex Structures in Hybrids

“…The MAG 13 fragment was found to be located on chromosome 2, and the MAG 7 and MAG 17 fragments are located on chromosome 5 for E. talpinus ( fig. 2 ), which clarifies published findings Lemskaya et al, 2010] A karyotype comparison between E. tancrei and E. talpinus using M. agrestis autosomal probes revealed complete chromosome homology between these mole vole species, with the exception of one pair of chromosomes, Nr. 7, which is located precisely at the position of the centromere.…”

Chromosomal evolution in Rodentia

“…A comparison of eight Microtus species using M. agrestis painting probes allowed reconstruction of a putative ancestral karyotype and insights to karyotype evolution within the taxon . Surprisingly, cross-species chromosome painting in Microtus revealed no rearrangements that clearly support the branching pattern depicted in the molecular tree (see Lemskaya et al, 2010). Karyotypes of grey voles are generally characterized by the conservation of large ancestral syntenies suggesting that Robertsonian translocations predominate in the karyotype evolution of these species (Li et al, 2006b;Lemskaya et al, 2010).…”

“…It comprises: MMU 1/14/1, 1/17, 1/17/7/5/10/17, 2, 2, 2/13, 3, 3, 4, 4, 5/11, 5/16, 6, 6/12/17, 7, 7/19, 8, 8, 9, 10, 11/17/16, 12, 13/15, 14, 15, 17/1/10/17, 18, X and Y. The ancestral Microtus karyotype (AMiK, Lemskaya et al, 2010) can therefore be derived by one fusion, that of MMU 6 and MMU 6/12/17, which resulted in the formation of MMU 6/17/12/6. Sigmodontinae A high degree of karyotype conservation was revealed for eight species of Sigmodon (Swier et al, 2009).…”

“…Reciprocal chromosome painting between mouse/ golden hamster and golden hamster/field vole (Romanenko et al, 2006;Lemskaya et al, 2010) provided an opportunity to include cricetid and arvicolin comparisons in the myomorph investigation. Here, we examined the karyotype evolution of Muroidea based solely on mouse chromosome associations.…”

Comparative Cytogenetic Study of Two Sister Species of Iberian Ground Voles, <i>Microtus (Terricola) duodecimcostatus </i>and <i>M. (T.) lusitanicus</i> (Rodentia, Cricetidae)

“…The diploid 2n = 54 karyotype is considered a primitive feature within the genus [Zima and Král, 1984;Lemskaya et al, 2010]. The only species of Microtus (Terricola) that show increasing diploid and fundamental numbers, with respect to the primitive one, are the 2 Iberian species.…”