Holarctic phylogeography of the root vole (Microtus oeconomus): implications for late Quaternary biogeography of high latitudes

Abstract

A species-wide phylogeographical study of the root vole (Microtus oeconomus) was performed using the whole 1140 base pair mitochondrial (mt) cytochrome b gene. We examined 83 specimens from 52 localities resulting in 65 unique haplotypes. Our results demonstrate that the root vole is divided into four main mtDNA phylogenetic lineages that seem to have largely allopatric distributions. Net divergence estimates (2.0-3.5%) between phylogroups, as well as relatively high nucleotide diversity estimates within phylogroups, indicate that the distinct phylogeographical structure was initiated by historical events that predated the latest glaciation. European root voles are divided into a Northern and a Central mtDNA phylogroup. The mtDNA data in concert with fossil records imply that root voles remained north of the classical refugial areas in southern Europe during the last glacial period. The currently fragmented populations in central Europe belong to a single mtDNA phylogroup. The Central Asian and the North European lineages are separated by the Ural Mountains, a phylogeographical split also found in collared lemmings (Dicrostonyx) and the common vole (M. arvalis). The Beringian lineage occurs from eastern Russia through Alaska to northwestern Canada. This distribution is congruent with the traditional boundaries of the Beringian refugium and with phylogeographical work on other organisms. In conclusion, similarities between the phylogeographical patterns in the root vole and other rodents, such as Arctic and subarctic lemmings, as well as more temperate vole species, indicate that late Quaternary geological and climatic events played a strong role in structuring northern biotic communities.

Pliocene and Pleistocene diversification and multiple refugia in a Eurasian shrew (Crocidura suaveolens group)

“…The results support the monophyly of the Crocidura suaveolens group, which exhibit substantial mitochondrial and nuclear DNA structure across its Eurasiatic range. The seven identiWed phylogeographical clades are ancient, reXecting isolation during Pliocene climatic Xuctuations and Pleistocene glaciations, and likely to have survived in southern refugia during recurrent Ice Ages, as shown in the root vole (BrunhoV et al, 2003;Galbreath and Cook, 2004) and the woodmouse (Michaux et al, 2003). The Western European barriers isolating the populations are those commonly accepted; in contrast, eastern barriers, such as the 'Anatolian Diagonal' and the Caucasus Mountains, are not as well known.…”

“…Notwithstanding some holartic species (BrunhoV et al, 2003) and scant data for temperate species (Ohdachi et al, 2001;Yasuda et al, in press), there are no well-documented phylogeographies encompassing the whole Palaearctic, in spite of the fact that such data may highlight the interrelationships between the Quaternary histories of Asian and European biota and improve our general knowledge of Quaternary refugia in central and eastern Asia. Moreover, such information is relevant for understanding and conserving the current biological diversity in that part of the world.…”

“…Several authors, however, suggest an additional mode of colonisation of central and northern Europe by non-Mediterranean populations, coming from one or more eastern refugia: Caucasus, southern Ural, central Europe, and western Asia (Bilton et al, 1998;Cooper et al, 1995;Michaux et al, 2004;Nesbo et al, 1999;Palme and Vendramin, 2002;Seddon et al, 2002). A few other species (BrunhoV et al, 2003;Taberlet et al, 1998) …”

Geography and host biogeography matter for understanding the phylogeography of a parasite

“…1). Similarly, some species such as the brown bear (Ursus arctos) (Taberlet et al, 1998) or different small mammal species [Clethrionomys glareolus (Deffontaine et al, 2005); Sorex minutus and S. araneus (Bilton et al, 1998) and M. arvalis (Jaarola and Searle, 2004) and M. oeconomus (Brunhoff et al, 2003)] display genetic lineages suggesting that these species also survived in more easterly refuges (the Caucasus or the southern Urals) and in Central Europe (Kotlı´k et al, 2006). Moreover, the examination of the fossil record of European temperate species during the last ice age (26000-13000 years ago) reveals that environmental conditions were not severe enough in these regions to prevent the survival of forest-dependent species, notably in Poland (Sommer and Nadachowski, 2006).…”

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“…root vole (Microtus oeconomus; Brunhoff et al 2003) and reed bunting (Emberiza schoeniclus; Zink et al 2008)), or peninsula populations are isolated (e.g. great bustard (Otis tarda; Pitra et al 2000)).…”