DNA integrity in Asterias rubens: a biomarker reflecting the pollution of the North Sea?

To assess the health status of the North Sea, DNA damage in seastar (Asterias rubens L.) was studied by establishing the level of integrity of DNA (strand breaks) isolated from pyloric caeca of these organisms, collected at 16 places in the southern half of the North Sea. On the basis of the fraction of intact double-stranded DNA (F-value) the sampling locations were classified into three clusters: cluster 1, an area (Dutch coastal zone and a deeper zone near the English coast) with a low DNA integrity (F < 0.50, which means that more than 50% of the DNA exhibited strand breaks); cluster 11, areas (coastal sites in the Southern and German Bights and the offshore region of the Dogger Bank) with intermediate integrity of DNA (0.50 < F < 0.75), and cluster 111, an area (central part of the southern North Sea, south of the Dogger Bank) with high DNA integrity (F > 0.75, indicating that less than 25% of the DNA exhibited strand breaks).