Genetic structure and colonization processes in European populations of the common vole, Microtus arvalis

• The level of genetic differentiation within and between evolutionary lineages of the common vole (Microtusarvalis) in Europe was examined by analyzing mitochondrial sequences from the control region (mtDNA) and 12nuclear microsatellite loci (nucDNA) for 338 voles from 18 populations. The distribution of evolutionary lineagesand the affinity of populations to lineages were determined with additional sequence data from the mitochondrialcytochrome b gene. Our analyses demonstrated very high levels of differentiation between populations (overall FST:mtDNA 70%; nucDNA 17%). The affinity of populations to evolutionary lineages was strongly reflected in mtDNAbut not in nucDNA variation. Patterns of genetic structure for both markers visualized in synthetic genetic mapssuggest a postglacial range expansion of the species into the Alps, as well as a potentially more ancient colonizationfrom the northeast to the southwest of Europe. This expansion is supported by estimates for the divergence timesbetween evolutionary lineages and within the western European lineage, which predate the last glacial maximum(LGM). Furthermore, all measures of genetic diversity within populations increased significantly with longitude andshowed a trend toward increase with latitude. We conclude that the detected patterns are difficult to explain only byrange expansions from separate LGM refugia close to the Mediterranean. This suggests that someM. arvalis populationspersisted during the LGM in suitable habitat further north and that the gradients in genetic diversity may representtraces of a more ancient colonization of Europe by the species.

Ämnesord

NATURVETENSKAP  -- Biologi -- Evolutionsbiologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences -- Evolutionary Biology (hsv//eng)

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