Figure 2.

Prominent role for trans-regulatory divergence in the evolution of cichlid opsin expression. Divergence at 11 overlapping eQTL located both cis- (LG 5) and trans- (LGs 1, 10, 15, and 23) to the opsins contributes to interspecific differences in cichlid opsin expression and color vision (n = 115). eQTL on linkage group 5 are considered potential cis-regulatory loci given their linkage to the opsin genes on this chromosome; however, it is also possible that some or all of these regions contain diffusible regulatory elements that act in trans. LOD plots of eQTL and their associated opsins are shown for significant eQTL only. Horizontal bars represent the 95^th percentile of genome-wide LOD scores (LOD = 3.7) and colored rectangles delineate the 95% Bayesian confidence intervals for each eQTL. Tic-marks above the x-axis indicate the position of each genetic marker, while the white boxes indicate the genomic scaffolds that these markers map to within the Metriaclima zebra cichlid genome assembly (not to scale). A linkage map with marker names is shown to the right of each LOD plot. Colored bars and highlighted marker names correspond to the 95% Bayesian confidence intervals shown in the LOD plots (for LG 10, drop 2-LOD are used).