Artificial environmental conditions can affect allozyme genetic structure of the marine gastropod Patella caerulea

Samples of the Mediterranean limpet Patella caerulea collected from 10 sites were examined for genetic population structure. Six of the 20 identified enzymatic loci were polymorphic. The AAT* locus was polymorphic only in two samples from an artificial environment (TI2 and PE). The proportion of polymorphic loci ranged from 0.20 to 0.30, and the observed and expected mean heterozygosity varied between 0.098 and 0.076 and between 0.109 and 0.086, respectively. Mean Fis values were significantly positive in AAT*, ESTD*, PEPC-2*, and PEPD*, showing heterozygosity deficiency. In all, mean Fst value of 0.007 indicated high genetic homogeneity between the samples analyzed, whereas single-locus Fst analysis showed an interesting case of significant microscale genetic heterogeneity in AAT* (Fst = 0.158, P < 0.001). The specimens collected from the two artificial environments (TI2 and PE) were responsible for AAT* heterogeneity. These results, as suggested by other authors, could be related to the hydrodynamic conditions of artificial environments.