Numerical chromosomal aberrations in the early life-history stages of a marine tubeworm, Pomatoceros lamarckii (Polychaeta: Serpulidae).

The marine environment provides a sink for a host of toxic chemicals, directly or inadvertently, released as a result of human activity. Some of these chemicals have the potential to act as aneugens, substances that cause numerical chromosomal aberrations (NCAs). NCAs are one of the most important classes of genetic abnormality and are implicated in a variety of deleterious effects, including premature ageing, birth defects and cancer. Clearly, any increase in the incidence of these agents in the marine environment poses a risk to the indigenous biota and its predators, including man. In this paper, we describe our recent success with applying the fluorescence in situ hybridisation technique (FISH) to detect NCAs in the interphase cell nuclei of Pomatoceros lamarckii, a common rocky shore invertebrate. Given the lack of requirement for any detailed cytogenetic knowledge, the method holds considerable promise for laboratory and field studies in general, and should lend itself to automated screening protocols, where large numbers of cells can be screened rapidly, for example, using a flow cytometer. When exposed either under acute or chronic (viz. adult) exposure conditions, colchicine and di-butylphthalate (DBP) (a widely-used plasticiser), two recognised aneugens, induced significant increases in the levels of NCAs, in the dose range 1 x 10(-6)-5 x 10(-6) M, in both four to eight cell embryo stages and 24 h-old larvae. In keeping with the severely debilitating effects of this class of agent, an inverse correlation was observed between the induced levels of NCAs and larval fitness based on the results of a standard 48-h larval bioassay.