Identification and characterization of expressed sequence tags from the liver of rare minnow (Gobiocypris rarus)

Rare minnow (Gobiocypris rarus) is a newly developed aquatic test organism that has been widely used in a range of studies of toxicological risk assessment by virtue of its higher sensitivity to xenobiotics. To describe extensively the transcripts expressed in the livers of adult rare minnow, we generated 6919 high-quality expressed sequence tags (ESTs) from a non-normalized cDNA library. After processing, a total of 1773 unigenes (unique genes) comprising 771 contigs (consensus sequences) and 1002 singlets were acquired. Based on the analysis by BLAST, 1512 unigenes (85%) had been identified and annotated. The result of functional classification reveals that the genes involved in the processes of general metabolism prevail in liver expressed genes. In addition, we compiled a potentially toxicology-related catalog comprising 262 unigenes that associated with metabolism of xenobiotics and adaptive responses. There are eleven groups referring to diverse functions in the catalog. This report provides the first set of genetic data for rare minnow which is of great value for further exploitation of this species in functional genomics and toxicogenomics, and sets a basis for the discovery of new molecular markers of exposure and for the production of the function-focused microarray.