An economical and rapid method of comet assay and micronucleus cytome assay for genotoxicity biomonitoring using clam, Gafrarium divaricatum (Gmelin, 1791)

The comet assay or single-cell gel electrophoresis and the micronucleus cytome assay have emerged as widely used methods for measuring DNA damage and cytotoxicity in genotoxicity testing and biomonitoring studies. The relative occurrence of micronuclei and other cellular abnormalities in dividing cells is a reliable biomarker of xenobiotic-induced genotoxicity. Bivalves are known for their bioaccumulation capabilities and are ideal bioindicators for monitoring DNA damage and chromosomal mutations. This study focuses on the optimization and standardization of genotoxicity assays, such as comet assay and micronucleus test, using forked venus clam, Gafrarium divaricatum, as a model organism. It highlights the potential of using cost-effective mechanical digestion method to prepare cell suspensions from clam tissues, as opposed to the more expensive enzymatic digestion techniques. It also explored the application of various staining techniques to improve the accuracy of micronucleus scoring, addressing the variability in genotoxicity assays across different laboratories. By developing a species specific standardized protocol for these assays, this investigation aimed to reduce inter-laboratory discrepancies and enhance the reliability of genotoxicity testing in marine organisms, especially in bivalves, thereby facilitating regulatory applications and environmental monitoring.