GENETIC DEPLETION IN THE EUROPEAN BISON (BISON-BONASUS) AND THE SIGNIFICANCE OF ELECTROPHORETIC HETEROZYGOSITY FOR CONSERVATION

Starch gel electrophoresis was used to screen 35 lowland bison from th e herd in the Bialowieza Primeval Forest for genetic variation at 69 p resumptive structural loci. Average heterozygosity (H = 1.2%) proved t o be three times lower than that based on 20 loci (H = 3.5%) reported in a previous study by other authors, These earlier results were inter preted as evidence that the passage of the species through an extreme genetic bottleneck (12 founder genomes) bad not bad much influence on genetic variation. A comparison of estimates of H and the proportion o f polymorphic loci (P) among different species or populations of Artio dactyla revealed that P was the only parameter to be significantly red uced in those that bad experienced genetic bottlenecks. However, the d ata also show that, in spite of similar H values in species or populat ions with or without bottlenecks, average heterozygosity is only usefu l as an indicator of overall genetic variability in the latter. To dra w conclusions about genetic depletion on the basis of electrophoretic data, we strongly recommend that H, together with its variance among a large number of loci, and additional parameters such as P and the rat io H:P be taken into account.