Unusual electrophoretic patterns for phosphoglucomutase and fumarase in a population of Lecithochirium rufoviride (Trematoda : Hemiuridae), a parasite of Conger conger

Electrophoretic analyses of phosphoglucomutase (PGM) and fumarase (FH) in a population of Lecithochirium rufoviride parasitizing Conger conger, reveal ed 2 independent activity zones for each enzyme on starch gel electrophores is. However, some individuals exhibited only 1 activity zone for 1 or both enzymes. The banding patterns observed strongly suggest that (1) PGM is cod ed by 2 polymorphic loci, Pgm-1 (expressed in all individuals) with allelic frequencies not significantly different from those expected under Hardy-We inberg equilibrium, and Pgm-2 (expressed in a subset of individuals); and ( 2) FK is coded by 2 loci, Fh-2 (monomorphic and expressed in ail individual s) and Fh-1 (expressed in a subset of individuals). A high degree of concor dance (88.75%) was observed between the expression and nonexpression of Pgm -2 and Fh-1. The most likely explanations for these fmdings are either vari ation in enzyme expression with developmental stage or the presence of null alleles at high frequencies in the population.