Figure 4.

Comparison of transcript levels exhibiting inter-strain variability determined by analyses of individual samples and pooled samples. (a) Examples of genes that demonstrated significant inter-strain variance after pooling the RNA from three mice of each strain. The relative expression values are shown for the three mice individually (1, 2, 3) and for the three mice pooled (P). Note that the individual and pooled results are data from independent hybridizations. Q-values are listed for both the individual mouse experiment (q1) and the pooled mouse experiment (q2), and values less than 0.1 are shaded gray to indicate statistical significance. Genes with low intra-strain variability (stable within strain) were statistically significant in both the individual and pooled experiments, while genes that had large intra-strain variability (noisy within strain) were significant only in the pooled experiment. Asterisks denote genes that were verified by quantitative PCR. (b) Genes such as Cth were relatively stable within strain. (c) Genes such as CisH were relatively noisy within strain. Error bars indicate standard deviations of four microarray experiments.