Electrophoretic enzyme comparison of wild and laboratory tsetse fly populations of glossina pallidipes and G. Brevipalpis (diptera: glossinidae)

Abstract

An electrophoretic comparison of 11 randomly selected enzyme systems was made between two laboratory colonies of Glossina pallidipes and one of ~. brevipalpis with their corresponding ancestral wild populations. The samples were compared with regard to the amount of genetic variation within each population. The genetic variability in each population was measured by calculating the proportion of polymorphic loci(P), and the average heterozygosity per locus. Other parameters considered for comparison were:- allele frequency data, the number of alleles per locus and effective number of genotypes at each locus. To quantify the extent to which the colony flies carried electromorphs similar to those found in natural tsetse, the identity statistics, (Nei, 1972) and the standard distance between field and colony flies were calculated. As a partial test of the genetic interpretation of the observed variations, the electrophoretic patterns of the polymorphic loci were examined for their goodness of fit with regard to expectations based on Hardy Weinberg equilibrium model. Of the 11 enzyme systems, only nine were consistently scorable. The important observations of these investigations are that the field flies were genetically approximately the same as those of the laboratory samples. There was no difference as regards the percentage of polymorphic loci. The difference in allozyme frequencies were not statistically significant. The identity values between field and laboratory samples were high and genetic distances small, showing that the laboratory stocks were still closely related to their ancestral wild populations. It was concluded that colonization has had no significant change on genetic variations within the colony flies.