Radiation events in the subfamily Arvicolinae (Rodentia): Evidence from nuclear genes

Abstract

Voles and lemmings (subfamily Arvicolinae) areone of the youngest and speciesrich groups of myomorphic rodents prevailing in different landscapezones of the northern hemisphere. Because of unprecedented fossil records, as well as rapid and continuingmorphogenesis, they became leading forms in correlation and biostratigraphy of late Cenozoic continentaldeposits. For the same reasons, they are an almostideal model group for testing various evolutionary scenarios and phylogenetic hypotheses on the one hand,and for comparison of the possibilities and limitationsof different methodical approaches to phylogeny analysis and system generation, on the other hand.This study consisted in analysis of two nuclear genevariation, which demonstrated that mole lemmings(Ellobuisini), steppe lemmings (Lagurini) and grayvoles (Arvicolini) were sister groups. This divergencewas the latest, third step of subfamily radiation. Thenew data on close sister relationships of mole lemmings, gray voles, and steppe lemmings and on the latemole lemming radiation are unexpected and contradictory to traditional views.Originally, system generation and relationshipanalysis within the subfamily were based on comparatively studying the morphological traits in the modernand extinct forms; the most important results werereported in summary monographs and articles [1–4].As new approaches (karyological, allozyme analysis, molecular methods) appeared, modified schemeswere developed based on the new data [5–12]. Comprehensively studying the group revealed some distincthigher categories of the tribal rank in all summariesand systems, including the latest ones [11]. At thesame time, their composition, relationships, and thetime of divergence still remain obscure. Morphological approaches fail to reconstruct the evolutionary history and relationships of such a young and rapidlyevolving group because of a few available traits andnumerous parallelisms.The study of Arvicolinae molecular phylogeny hasbeen so far based on the mitochondrial cytochrome