Why Sequence Catfish?

Catfish are a two-billion-dollar industry in the United States, representing 68% of all U.S. aquaculture production. Catfish have served as model species for comparative immunology, reproductive physiology, and toxicology among ectothermic vertebrates because of their unique characteristics. This project involves sequencing expressed sequence tags (ESTs) for two closely related catfish species.

Channel catfish (Ictalurus punctatus) and a member of the same genus, blue catfish (Ictalurus furcatus), share an average of 98.7% gene sequence identity but manifest important differences in economically important traits, such as disease resistance and growth. The two species produce fertile hybrids that not only have the potential to revolutionize the catfish industry, but also provide unique opportunities for genome and quantitative trait locus (QTL) mapping. However, genome-based technologies are not yet available for marker-assisted selection, and research in catfish has reached a bottleneck because of a lack of ESTs for functional genomic studies and genome mapping. This project will relieve this limitation by capturing the vast majority of the catfish transcriptome, allowing rapid gene discovery, identification, and annotation. The ESTs will serve as the basis for the development of cDNA miroarrays that are fundamentally important for the analysis of genome expression in relation to function.

The two-species approach will bring three additional benefits. First, it will allow the most efficient identification of gene-associated polymorphic markers, the mapping of which would set the foundation for comparative genome analysis in catfish. Second, it will allow identification of duplicated genes, allowing comparative genome analysis of the teleost-specific gene duplications. Third, it will allow identification of a pool of candidate genes potentailly responsible for differences in important traits between the two species.

CSP project participants: John Liu (proposer, Auburn Univ.), Sylvie Quiniou and Geoffrey Waldbieser (USDA), John Trant (Univ. of Maryland), and Melanie Wilson (Univ. of Mississippi).