Biomarkers of DNA damage in marine mammals

Certain environmental contaminants found in marine mammals have been shown to cause DNA damage and cancer. The micronuclei (MN), sister chromatid exch ange (SCE) and/or chromosome aberration (CA) assays were used to assess bas eline (spontaneous) levels of DNA damage in blood lymphocytes of individual s of the relatively healthy and lightly contaminated Arctic beluga whale (D elphinapterus leucas), Sarasota Bay, FL, bottlenose dolphin (Tursiops trunc atus) and Northwestern Atlantic grey (Halichoerus grypus) and harp (Phoca g roenlandicus) seal populations. MN cell (MNC) frequencies ranged between 2 and 14/1000 binucleated (BN) cells and were statistically similar between s pecies. In bottlenose dolphins, MNC frequency was correlated with age and w as significantly higher in females than in males. No intraspecific variatio n in MNC frequency was found in beluga whales. Intraspecific variation was not tested in seals due to the small sample size. Frequencies of SCEs and t otal CAs, excluding gaps, ranged, respectively, between 1 and 15 SCE(s)/per cell and 4-6 CAs/100 cells in beluga whales. SCE and CA frequencies did no t vary with age or sex in beluga whales. The MN, SCE and CA assays were fou nd to be practical tools for the detection of DNA damage in marine mammals and could be used in the future to compare DNA damage between relatively li ghtly and highly contaminated populations. (C) 1999 Elsevier Science B.V. A ll rights reserved.