Volume of expression by position with respect to segment boundaries – estimated from expression data. With respect to (a) A+/T+ boundaries; (b) T+/A+ boundaries. For both graphs, the unsymmetric black line shows the volume of transcription along one strand from left to right – transcription with the flow of the segment bias is on the right for (a), and on the left for (b). The peak is about 15 kb to 20 kb downstream/upstream of the segment boundary. Corresponding data for both sides of the boundary have been averaged. The upper red line plots the sum of the amounts on the two strands and the blue line plots their absolute difference. All three lines show moving averages over 100 bases and the thickness of the lines show 95% confidence limits. For both (a) and (b), a two-tailed z-test shows that the black line at position +5000 bases is statistically different from that at position -5000: a) p < 10-50, n1 ~ 2058, n2 ~ 856, z = 16.5: b) p < 10-50, n1 ~ 2253, n2 ~ 1260, z = 16.6.
Evans BMC Genomics 2008 9:16 doi:10.1186/1471-2164-9-16