NRSE profile and distribution of log-odds score. (a) Position weight matrix of NRSE at 21 positions constructed from 38 known NRSE sites. The y-axis represents the information content at each position. (b) The average number of bases mutated in orthologous regions of mouse, rat or dog at each position of the NRSE profile, when the nonhuman sequences are compared with the corresponding human site. The number is calculated based on the 37 known NRSE sites that can be aligned in the four species. (c) Distribution of background NRSE log-odds score calculated over regulatory regions (from upstream 5 kb to downstream 5 kb around each transcriptional start) of all human protein-coding genes. (d) Distribution of NRSE log-odds score on 895 identified NRSE sites.