mtDNA evidence for a local northern latitude Pleistocene refugium for the root vole (Microtus oeconomus, Arvicolinae, Rodentia) from Eastern Poland

Abstract

We analysed the genetic structure of 33 populations of the root vole (tundra vole, Microtus oeconomus, Pallas, 1776) inhabiting their typical habitats, located at different distances from the southern boundary of the species' range (52°14 0 -53°56 0 N) in eastern Poland. We determined its phylogeographic pattern as well as the possible occurrence of a small, local high-latitude refugium of this species in southern Poland, previously suggested in palaeontological studies. 908 bp of cytochrome b sequences were analysed from 439 root voles, and 21 mtDNA cytb haplotypes belonging to the Central European (CE) phylogroup were found. Haplotype diversity in the examined populations varied between 0 and 0.872 (mean: 0.425 AE 0.332), while nucleotide diversity ranged between 0 and 0.62% (mean: 0.235% AE 0.217). Within the CE phylogroup of M. oeconomus, we identified with high bootstrap support a newly separated group of M. oeconomus that evolved from CE, denoted CE-PL S. This group is located in the southern and central part of eastern Poland and most likely diverged from phylogroup CE in a small, cryptic refugium situated in southern Poland, in the Krak ow-Cze z stochowa Upland and/or the Holy Cross Mountains during the LGM and Younger Dryas.

Low Genetic Variability of the Tundra Vole in Lithuania

“…Three cytb haplotypes (C1, C5, and C9) were shared by A. oeconomus sampled in Poland and Lithuania. These haplotypes were detected in northeastern Poland, see locations 1-14, 16, 18, 20, and 21 in Figure 1 from Janczewicz et al [27]. In more detail, C1, the most commonly identified haplotype in Lithuania, was detected at 15 different sites in Poland.…”

“…For cytb analysis, 341 sequences were retrieved from GenBank (AB372193-AB372207 [35], AY219981-AY220045 [19], DQ452134-DQ452142 [14], FJ986325-FJ986326 [36], GU954319, GU987116 [37], KP190236-KP190237, KP326574 [38], KP684101-KP684121 [27], MF099520-MF099521, MF099544-MF099546, MF099577, MF099579-MF099581 [39],…”

“…For cytb analysis, 341 sequences were retrieved from GenBank (AB372193-AB372207 [35], AY219981-AY220045 [19], DQ452134-DQ452142 [14], FJ986325-FJ986326 [36], GU954319, GU987116 [37], KP190236-KP190237, KP326574 [38], KP684101-KP684121 [27], MF099520-MF099521, MF099544-MF099546, MF099577, MF099579-MF099581 [39], and AY305050-AY305263 [40]). Some of the sequences obtained from GenBank, namely AY219983, AY219986, AY219987, AY219989-90, AY219995, AY220007, AY220010, AY220014, AY220025, AY220027-9, AY220032, AY220036-7 [19], DQ452135, DQ452137, DQ452142 [14], KP684101-9, KP684111-4, KP684116, and KP684118 [27], were identified in 2-122 voles, and all remaining sequences were detected once. It should be noted that one of the sequences, AY220011, was previously obtained from A. oeconomus collected in the southern part of Lithuania (Žuvintas Strict Nature reserve) [19].…”

“…The relatively low genetic variability of Lithuanian populations of A. oeconomus found in this study should be considered an exception in the European part of the species' range. Notably, high genetic diversity in mtDNA has been found in A. oeconomus collected in different regions of Europe [19,22,27], including modern populations on the Norwegian islands, living in harsh climatic conditions [14].…”

“…Therefore, migration from the Polish population to Lithuania was presumed. This part of Poland has strong populations of the species [27] as a result of postglacial dispersal and configuration of hydrogenic habitats [28]. In the 1990s, the largest number of registrations was in southern and southwestern Lithuania.…”