Table 2 A matrix describing the correlation between mean gene expression profiles of amplified and unamplified M. tuberculosis total RNA from 500, 50 and 5 ng starting amounts. Spearman's rank correlations were calculated from the mean RNA signals from all M. tuberculosis H37Rv genes. Correlations in bold type highlight the relationship between differing input amounts of RNA using the same amplification method, oligo-dT or ADP. The correlations between unamplified (Unamp) and amplified products are marked in italics.