Expression data for unamplified and amplified cDNA demonstrate that all methods introduce errors to microarray expression data. Column 1 represents averaged expression data for dye-swap hybridizations of two technical replicates from the same starting RNA. Column 2 represents averaged expression data for four hybridizations including dye swaps comparing gene expression between two different cell types (3T3 vs OV). (a) Unamplified cDNA; (b) T7-based amplification; (c) global polyadenylated PCR-based amplification technique; (d) SMART amplification; (e) Modified SMART amplification. CR, coefficient of repeatability, a measure of the repeatability of hybridizations, with lower values representing similar hybridizations (see text for details of calculation).
Subkhankulova and Livesey Genome Biology 2006 7:R18 doi:10.1186/gb-2006-7-3-r18