Evaluation and characterization of a porcine small intestine cDNA library: analysis of 839 clones.

A porcine small intestine directionally cloned cDNA library was constructed in the vector lambda Zap II. Clones were hybridized with total labeled cDNA such that putative high-copy number transcripts could be differentiated from middle- and low-copy number transcripts prior to selection and characterization by DNA sequencing. More than 2000 non-hybridizing and 242 hybridizing clones were collected. In total, 839 clones were sequenced from the 3' end of the cDNA, and after inter-clone comparison, the unique clones were sequenced from the 5' end of the cDNA. The 5' data were used to query the sequence in databases and resulted in the identification of 630 different gene transcripts, of which 604 are new porcine genes. The identity of 361 transcripts could be identified from sequence comparison studies. The validity of this semi-random selection approach was verified by the identification of a large number of unique transcripts.