M. Jaarola et H. Tegelstrom, COLONIZATION HISTORY OF NORTH EUROPEAN FIELD VOLES (MICROTUS-AGRESTIS) REVEALED BY MITOCHONDRIAL-DNA, Molecular ecology, 4(3), 1995, pp. 299-310
The genetic structure of field vole (Microtus agrestis) populations fr
om northern Europe was examined by restriction fragment length polymor
phisms of mitochondrial DNA (mtDNA) in 150 individuals from 67 localit
ies. A total of 83 haplotypes was observed, most of which were rare an
d highly localized geographically. Overall nucleotide diversity was hi
gh (1.34%),but showed a tendency to decrease with higher latitude. Two
major mtDNA lineages differing by 2% in nucleotide sequence were iden
tified. A southern mtDNA lineage was observed in field voles from Brit
ain, Denmark and southern and central Sweden, whereas voles from Finla
nd and northern Sweden belonged to a northern lineage. The strict phyl
ogeographic pattern suggests that the present population genetic struc
ture in field voles reflects glacial history: the two groups are deriv
ed from different glacial refugia, and recolonized Fennoscandia from t
wo directions. A 150-200-km-wide secondary contact zone between the tw
o mtDNA groups was found in northern Sweden. Distinct phylogeographic
substructuring was observed within both major mtDNA groups.