ALLOZYMIC VARIATION AND DIFFERENTIATION IN MOLES (GENUS TALPA, INSECTIVORA) OF THE VAL-BREGAGLIA (SWITZERLAND) AND THE VAL-CHIAVENNA (ITALY)

Allozymic variation and differentiation of strictly parapatrically dis tributed European moles (Talpa europaea, n = 44) and Mediterranean mol es (T. caeca, n = 34) were studied in the Val Bregaglia (Switzerland) and Val Chiavenna (Italy) to estimate interspecific separation and int raspecific gene pool structuring. Tissue samples were screened for all elic variation at 44 putative gene loci using horizontal starch gel el ectrophoresis. In T. europaea four and in T. caeca three regional samp les separated from one another by water courses were discriminated. Th e proportion of polymorphic loci was 2.3 per cent in each regional sam ple, with polymorphisms at the Es-1 locus in T. europaea and at the Es -1 and the Es-D loci in T. caeca. Expected average heterozygosity rang ed from 0.6 to 1.2 per cent in regional samples of T. europaea and fro m 0.9 to 1.2 per cent in T. caeca. In T. caeca one regional sample sho wed fixation of a unique allele (Es-D-143). This indicated paucity of migration across surrounding water courses Inbreeding coefficients (F- IS) for the Es-1 locus ranged from 0.39 to 1.0 in regional samples. Si gnificant deviations of genotype frequencies for the Es-1 locus due to deficiency of heterozygotes were found in one T. europaea and one T. caeca regional sample, respectively. The findings are discussed with r espect to the parapatric pattern of distribution and the generally low gene pool variability of Talpa species found so far.