Sequence verification as quality-control step for production of cDNA microarrays

To generate cDNA arrays in our core laboratory, we amplified about 2300 PCR products from a human sequence-verified cDNA clone library. As a quality-c ontrol step, rye sequenced the PCR products immediately before printing. Th e sequence information was used to search the GenBank((R)) database to conf irm the identities. Although these clones were previously sequence verified by the company, we found that only 79% of the clones matched the original database after handling. Our experience strongly indicates the necessity to sequence verify the clones at the final stage before printing on microarra y slides and to modify the gene list accordingly.