Correcting for gene-specific dye bias in DNA microarrays using the method of maximum likelihood

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Abstract
Motivation: In two-color microarray experiments, well-known differences exist in the labeling and hybridization efficiency of Cy3 and Cy5 dyes. Previous reports have revealed that these differences can vary on a gene-by-gene basis, an effect termed gene-specific dye bias. If uncorrected, this bias can influence the determination of differentially expressed genes. Results: We show that the magnitude of the bias scales multiplicatively with signal intensity and is dependent on which nucleotide has been conjugated to the fluorescent dye. A method is proposed to account for gene-specific dye bias within a maximum-likelihood error modeling framework. Using two different labeling schemes, we show that correcting for gene-specific dye bias results in the superior identification of differentially expressed genes within this framework. Improvement is also possible in related ANOVA approaches. Availability: A software implementation of this procedure is freely available at http://cellcircuits.org/VERA Contact:rmkelley@ucsd.edu Supplementary information: Supplementary data are available at Bioinformatics online.