Figure 1

A depiction of common strategies for microarray experimental design. A) Each sample is tested against a single, common standard. B) A pooled sample, made up of equal parts of a number of samples, is used for comparison to the samples of interest. C) Each strain is compared head-to-head with other strains in a circular fashion, or, D) with added cross-comparisons, a multiple-pairwise fashion. This last example is a classical balanced block design, with dye swaps.