Cytogenetic and isozymic comparisons of two laboratory lines ofGlossina palpalis gambiensis

Isozymic comparison of five laboratory lines of tsetse flies belonging to the two subspecies of Glossina palpalis Diptera: Glossinidae

“…MA and BO, although from the same sub-species and the same geographical locality, did differ from each other in the allelic pattern at the two MDH loci, con® rming the differences observed earlier (Elsen et al, 1994). These differences are presum ably the result of genetic drift while these lines have been held in laboratory colonies, as Gooding (1990) proposed for laboratory lines of G. m. morsitans.…”

“…However, the parallel trends in these two indices are interesting and appear generally to re¯ect differences in the variability of the conditions under which each line has been maintained (Elsen et al, 1994), or the length of time each has been maintained under constant conditions of temperature, humidity and feeding method in the laboratory. Thus the lowest values for G and H were those for ZA (constant conditions since 1969), does not ® t this trend because its mean heterozygosity per locus, which lies between those of ZA and MA, is lower than expected.…”

“…For research involving laboratory lines, therefore, attention has to be paid to these differences before conclusions at the speci® c or subspeci® c level can be made and extrapolated to ® eld conditions. Genetic characterization of the lines employed is important for parasitologists because laboratory lines differ in their susceptibility to trypanosome infection (Elsen et al, 1994).…”

“…Mean genetic diversity was estimated as the H index (Nei, 1987) and mean genotype diversity as the G index (Ben Abderrazak, 1993); details of both indices were given by Elsen et al (1994). Nei' s standard genetic distances (Ds; Nei, 1972) were also calculated.…”

“…By investigating ® ve enzymes, Elsen et al (1994) demonstrated a signi® cant genetic difference between two laboratory colonies of G lossina palpalis gambiensis, which also differed in terms of vectorial competence. The genetic difference observed appears to be the result of differences in the breeding conditions under which the¯ies were maintained (Elsen et al, 1993) and genetic drift since the foundation of the lines.…”