To evaluate genetic variability within and between populations of two closely related snail species Semisulcospira libertina and Semisulcospira reiniana, enzymes coded for by 18 presumed loci were examined by starch gel electrophoresis.
The proportion of polymorphic loci and the expected average heterozygosity per individual for the S. libertina populations were 0.172 and 0.057, respectively. These for the S. reiniana populations were 0.114 and 0.039, respectively. Nei′s genetic distance value estimated between the two species was 0.1235.
Marked difference in allele frequency between the two species was observed at the MPI and 6PGD loci. Other five loci (ICDH-1, AAT, MDH-1, PHI and Est) were variable in some of the libertina populations, although the five loci were fixed for the wild type allele in all of the reiniana populations. Another locus PGM-1 was variable in both species. These loci seemed to be useful genetical markers for differentiating S, libertina from S. reiniana.