Abstract
Ascidians are marine invertebrate chordates. We have developed a large-scale oligo DNA microarray of the ascidian Ciona intestinalis. We initially obtained expression patterns of 10,000 genes of this animal during its life cycle. We have now constructed a novel risk assessment system for marine chemical pollutants using ascidian DNA microarrays. First, we identify genes up- or down-regulated after exposing ascidians to pollutants. Second, we estimate the effects of the pollutants on the ascidians using array data and information about the life stages highly expressing those genes. Third, to verify the estimation, we investigate the inhibitory effects of pollutants on embryogenesis and metamorphosis in ascidians. From DNA microarray data, we estimated that organotin compounds might affect embryogenesis and metamorphosis in ascidians. We performed bioassay using embryo and larvae and found that a low concentration of the chemicals completely inhibited ascidian embryogenesis and metamorphosis. Our new risk assessment system will be a valuable tool for monitoring marine chemical pollutants.
