Genetic Differentiation and Biochemical Polymorphism among Trichomonads

Isoenzyme electrophoresis was used to study levels of genetic differentiation among strains and clones of Trichomonas gallinae, Trichomonas vaginalis, Tritrichomonas foetus, Tetratrichomonas gallinarum, and Pentatrichomonas hominis. Strain variation was found within T. gallinae, T. vaginalis, and T. foetus, however, levels of enzyme polymorphism were greater in T. gallinae than in T. vaginalis or T. foetus. Isoenzyme genotypes were not a stable property of T. gallinae clones cultivated in vitro. Retrospective studies of T. gallinae SG and JB6 clones revealed that mutation occurred during in vitro cultivation. Heterozygotes of hexokinase-1 and phosphoglucomutase displayed 2 allomorphs in equal dosage, indicating that trichomonads are diploid for these protein loci. Phenetic clustering of the biochemical data suggests that levels of genetic divergence among the species studied are extensive.