Isoenzyme variation in the common shrew (Sorex araneus) in Britain, in relation to karyotype

Abstract

Samples of common shrews with an Aberdeen race, Oxford race and Hermitage race karyotype and from the OxfordHermitage hybrid zone were screened for genotype at six polymorphic enzyme loci. The common allele at all loci was the same in all samples suggesting that the degree of genie divergence between the karyotypic races is not great. However, shrews of the Aberdeen race appear to be somewhat distinct. There were differences in allele frequencies, range of alleles and heterozygosities at the Mpi-1, Pgm-2 and Pgm-3 loci between the Aberdeen race samples and samples of other karyotypic categories. The allele frequency variation across the Oxford-Hermitage hybrid zone is not substantially linked with karyotype frequency change, but there is notable allele frequency variation between close sites of similar habitat, particularly at the Pgm-2 and Pgm-3 loci. This suggests that gene flow between close sites may be reduced sufficiently in some instances to allow allele frequency change by genetic drift. This may have implications for the mode of origin of karyotypic races of common shrew.

Karyotypic variation in the common shrew (Sorex araneus) in Britain – a “Celtic Fringe”

“…Therefore, pr has been considered to be an Oxford Table 2 Isoenzyme allele frequencies and mean heterozygosities for each sample in comparison with previous data (Searle, 1985). of the Oxford and Hermitage race samples from south-eastern England (Searle, 1985).…”

“…Previous studies in Britain (Searle, 1985) and Sweden (Frykman et a!., 1983) have indicated that allele frequencies at the Mpi-1 locus may differ between karyotypic races of common shrew. The present study shows that in Britain there is, in fact, not a simple relationship between Mpi-1 allele frequencies and karyotypic race.…”

“…2.7.5.1) locus (Pgm-3). In a previous study, allele frequency differences were identified between Oxford and Hermitage race and Aberdeen race samples at these loci (Searle, 1985 fig. 1.…”

“…The karyotypes of other individuals were deduced from conventional preparations. The methods used for electrophoretic analysis of Mpi-1 and Pgm-3 follow Searle (1985). Tn some cases the animals used for isoenzyme studies were not the same as those karyotyped and vice versa.…”

Genetic distinctiveness of a village population of house mice: relevance to speciation and chromosomal evolution

“…A large proportion of the individuals caught were karyotyped at a laboratory base in the valley (Hauffe & Searle 1993) and, for all individuals, freshly frozen tissue samples were brought back to Britain on dry ice for long-term storage at k80 mC. Treatment of the tissue samples and the cellulose acetate electrophoresis followed the methodology in Searle (1985). To visualize supernatant malic enzyme, liver or kidney samples were used and the electrophoretic running buffer was 40 m Tris-10 m citrate, pH 7.6.…”