Biochemical relationships of the Holarctic vole genera (Clethrionomys, Microtus, and Arvicola (Rodentia: Arvicolinae))

Abstract
Transferrin (Tf), hemoglobin (Hgb), leucine aminopeptidase (LAP), 6-phosphogluconate dehydrogenase (6PGH), and glucose-6-phosphate dehydrogenase (G6PD) were examined by starch-gel electrophoresis in Holarctic Microtus oeconomus and Clethrionomys rutilus, Siberian Microtus hyperboreus and Clethrionomys rufocanus, and North American Microtus miurus, Microtus ochrogaster, Microtus pennsylvanicus, Arvicola richardsoni, and Clethrionomys gapperi. Thirty alleles of five to seven loci, the number depending on the presence or absence of one or two minor hemoglobin fractions, were identified in these species. Interspecific comparisons were based on the presence of at least one allele shared in common at the various loci. The closest biochemical resemblances occurred between populations of Holarctic M. oeconomus and C. rutilus. Clethrionomys gapperi and C. rutilus were quite similar but C. rufocanus was divergent. Observed resemblances between M. hyperboreus and M. miurus were not strong and do not support the inclusion of the former in the amphiberingian narrow-skulled vole group. Arvicola richardsoni, though seemingly close to M. pennsylvanicus, was quite divergent from all other species of Microtus at the LAP locus and warrants comparison with Palearctic Arvicola. Microtus ochrogaster and M. pennsylvanicus shared many similarities and served as reference samples.