Protein polymorphism in the fresh water snail Semisulcospira libertina

To evaluate genetic variability in 19 population samples of the fresh water snail Semisulcospira libertina, 10 enzymes coded for by 13 presumptive gene loci were examined by starch gel electrophoresis. The mean proportion of polymorphic loci and the mean heterozygosity value estimated for the 19 samples were 0.199 and 0.063, respectively. The mean F statistics of Wright (1943) was estimated over the four polymorphic loci (PGM, 6-PGD, MPI and PGI) for the snail populations to be 0.3615.