Genetic variation in a Tanzanian population of Glossina swynnertoni (Diptera: Glossinidae).

Adult Glossina swynnertoni Austen that emerged from puparia collected during 1989 and 1991 near Makuyuni, Tanzania, were examined by polyacrylamide gel electrophoresis. Fourteen of 17 enzymes were monomorphic. Midgut alkaline phosphatase (ALKPH), phosphoglucomutase (PGM), and glucose-6-phosphate isomerase (PGI) from the head and thorax were polymorphic. Banding patterns indicated that the locus for PGM was on the X chromosome and loci for ALKPH and PGI were autosomal. For the 17 loci studied, the mean heterozygosity per locus was 6.1 +/- 3.7% in the 1989 sample and 5.7 +/- 3.7% in the 1991 sample. The effective number of alleles per locus was 1.11 and 1.10 in these samples. This level of genetic variation was low compared with other populations of tsetse flies and indicated that the sample may have been drawn from a small inbred population or one that recently had gone through a genetic bottleneck.