Digital image processing for rapid analysis of differentially expressed transcripts on high-density cDNA arrays

Usage of filter arrays is becoming increasingly attractive for many research laboratories involved indetermination of gene-expression profiles. However analysis of numerous spots, representing genes or partial gene sequences (ESTs), is still tedious work involving the ordered analysis of vast amounts of numerical tabular data. We present a vapid and efficient method for the visual identification of differentially expressed targets on high-density cDNA filter arrays using standard laboratory equipment and standard software, which is available for free. The method we introduce provides an inexpensive alternative, and no changes in the experimental set up are required. Our results were verified by densitometric analyses performed with an established system.