Phylogeographic structure and mitochondrial DNA variation in true lemmings (Lemmus) from the Eurasian Arctic |
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Authors: | VADIM FEDOROV ANNA GOROPASHNAYA GORDON H. JARRELL KARL FREDGA |
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Affiliation: | Department of Genetics, Uppsala University, Box 7003, S-750 07 Uppsala, Sweden;Institute of Plant and Animal Ecology, Yekaterinburg, Russia;University of Alaska Museum, Fairbanks, USA |
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Abstract: | The geographic pattern of mtDNA variation in lemmings from 13 localities throughout the Eurasian Arctic was studied by using eight restriction enzymes and sequencing of the cytochrome b region. These data are used to reveal the vicariant history of Lemmus , and to examine the effect of the last glaciation on mtDNA variation by comparing diversity in formerly glaciated areas to the diversity in non-glaciated areas. Phylogenetic congruence across different Arctic taxa and association between observed discontinuities, and probable Pleistocene barriers, suggest that glacial-interglacial periods were crucial in the vicariant history of Lemmus. Differences in amount of divergence (2.1–9.1%) across different historical barriers indicate chronologically separate vicariant events during the Quaternary. Populations from a formerly glaciated area are no less variable than those in the non-glaciated area. Regardless of glaciation history, no population structure and high haplotype diversity were found within geographic regions. The lack of population structure indicates that populations with high ancestral haplotype diversity shifted their distribution during the Holocene, and that lemmings tracked a changing environment during the Quaternary without reduction of effective population size. |
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Keywords: | Beringia population structure glaciation gene flow vicariant events islands environmental changes Quaternary cytochrome b gene |
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