Fig. 3

Distribution of nucleosome positioning signals at SASs and PASs. a The sequences of 400-bp regions encompassing the SAS (where it has been annotated [51]) were retrieved for the first gene in all PTUs, b for all internal SASs, and c for all PASs in all PTUs. The number of oligo-dT or oligo-dA runs (7–14 bp) was determined for the sequences aligned at the annotated SASs and PASs and is shown as a value normalized to the number of sequences. The Fourier amplitude of the distribution of A–A dinucleotides at a 10-bp periodicity was determined in a sliding 128-bp window, and normalized to the number of sequences in the window. d The cumulative Fourier amplitude is shown in a range from −500 to +500 bp relative to the first SAS upstream of all PTUs, e relative to internal SASs in all PTUs, and f relative to the internal PAS in all PTUs. The location of the SAS or PAS is indicated by the vertical black line