Sexual compatibility among Trypanosoma brucei isolates from an epidemic area in southeastern Uganda.

For the first time, two clones of Trypanosoma brucei from the same epidemic area in southeastern Uganda were successfully crossed. The cotransmission experiments were as close to natural conditions as possible in that two uncloned isolates from wild-caught Glossina fuscipes fuscipes were directly cotransmitted in an initial recombination experiment. From the first uncloned progeny population, which revealed a majority of recombinants, two clones with different parental phenotypes [characterized by isocitrate dehydrogenase (ICD) analysis] were isolated. These clones were cotransmitted in a second recombination experiment. Nine clones could be isolated from two different progeny populations of the second experiment, and all showed a recombinant phenotype. These nine clones belonged to three different karyotypes with respect to the large chromosomes (1-3 Mb), which were different from those of either parental karyotype or the sum of both parental karyotypes. The results indicate that genetic recombination might well occur between trypanosome populations transmitted within the same epidemic area.