Correlations in transcription among five accessions during leaf and silique development. (a) The Pearson correlation coefficient for a given sample was calculated with nRHI for all the genes from each accession and the reference accession Col-0. Each bar represents the correlation of a particular accession as compared to Col-0 in the sample group. Note the common trend in reduction of the correlation during leaf and silique development for each organ. (b) The regression coefficient for a given sample was calculated with nRHI for all the genes from each accession (Y-values, regressor) and the reference accession Col-0 (X-values, predictor). Each bar represents the regression coefficient of a particular accession as compared to Col-0 in the sample group. The regression coefficient (b) was calculated as b = (ΣXiYi - (ΣXi)(ΣYi)/n)/(ΣXi2 - (ΣXi)2/n), where n is the total number of genes in either Col-0 or the sample to be compared (7,508 in this case). The error bar indicates the upper or lower limit of the 95% confidence interval for each of the given regression coefficients. The 95% confidence interval was calculated as b ± tα(2), (n-2)Sb, where tα(2), (n-2) is the t critical value at α = 0.05, two-tail, df = 7,506, and Sb is the standard deviation of b.
Chen et al. Genome Biology 2005 6:R32 doi:10.1186/gb-2005-6-4-r32