DNA damage as a biomarker of marine pollution: strand breaks in seastars (Asterias rubens) from the North Sea

The DNA damage in seastars (Asterias rubens) was studied by measuring the level of integrity of DNA isolated from pyloric caeca of the organisms in order to assess the state of pollution of the North Sea. The effect of various genotoxic chemicals on the integrity of DNA was determined by the level of double strandedness with respect to total DNA following time-dependent partial alkaline unwinding assay. On the basis of the level of integrity of DNA from seastars the study area was distinguished into three clusters: Cluster-I, the highly polluted area (coastal and estuarine zones) with low integrity of DNA (27-43% integrity), Cluster-II, the moderately polluted area (offshore region) with medium integrity of DNA (49-64% integrity) and Cluster-III, less polluted area (near Dogger bank region) with high integrity of DNA (70-87% integrity).