Figure 16

ACGT-skew for individual genes – long genes. The y-axis is the ratio ((A+C)-(T+G))/(A+C+G+T)) for introns (and also excluding the 50 bases at each end of the intron) as used in [16]. The plot is restricted to genes of at least 10 k bases. a) ACGT-skew for individual genes by proportion of times gene is expressed: The plot shows a correlation of -0.39 (n = 8352). Even for seldom expressed genes there is an average negative bias. b) ACGT-skew for individual genes by segment bias predictor: The plot excludes genes which extend more than 100 k bases from both A+/T+ and T+/A+ boundaries, and this explains the gap in the plot. The correlation is 0.43 (n = 9040). The predictor does not use any information about transcription other than the position of the gene with respect to the segment boundaries. In particular, no information about transcription bias is used in calculating the predictor.