Characterization of coastal sites by applying genetic and genotoxicity markers in Mytilus galloprovincialis and Tapes philippinarum.

Electrophoretic profiles of allozyme loci (Odh, Gpi, Idh, Pgm, 6Pgd) and early markers of genetic damage have been studied in parallel in Mytilus galloprovincialis and Tapes philippinarum from three coastai zones conceming the Venice Lagoon (off-shore, Malamocco outlet, inner industriaI district). The selected species are filter-feeding bivalves inhabiting the water column and bottom sediments, respectively. In generaI, heterozygosity values were higher in clams than in mussels. Interestingly, heterozygote deficiency was detected in both species, particularly in samples from the industrial area where significant levels of DNA adducts, cytogenetic alterations and DNA strand breaks were also detected. Further work is necessary to extend these data and to investigate the relationships between long-Iasting exposure to toxic and genotoxic contaminants and changes in the genetic structure of native mollusc populations.