Divergence among coding and non-coding regions in O. niloticus and M. zebra BAC sequences. A) Pairwise sequence divergence (Dxy) between O.niloticus and M. zebra for different coding and non-coding regions of the opsin-containing BACs. Average Jukes-Cantor-corrected Dxy is higher among 5' proximal promoter regions for each opsin. B) Venn diagram of proportion of shared and divergent TFBS and microRNA target sites among non-coding regions examined in this study. Opsin promoter regions exhibit slightly elevated proportions of divergent sites compared to either CNEs or 3'-UTRs. C) Comparison of proportion divergent TFBS/miRNA target sites (Pdiv) and pairwise sequence divergence (Dxy). Non-coding sequences with elevated Pdiv do not necessarily exhibit increased Dxy, even among proximal promoters regions. Filled points are those sequences with Pdiv values that differ significantly from 8% (see also Table 3).