Figure 1.

Filtering array data. It is essential to remove as many false positives as possible at the earliest stages of analysis. Random errors occurring in oligonucleotide array data were assessed by comparing three biologically independent control arrays to three other biologically independent control arrays. Genes with a t test p < 0.05 in this comparison are plotted (a). Comparison of these results with the frequency of genes differing at p < 0.05 between control and experimental triplicate arrays (b) were used to define a set of criteria based on present/absent, fold change, t test p value, and a signal threshold that minimized the estimated random error [31].