Figure 2

The AXIN2-CCDC46 locus. The human ortholog of an exon that was exapted into a regulatory function in teleosts is shown in the context of synonymous constraint elements (SCE), ENCODE histone marks in human embryonic stem cells indicative of enhancer function and promoter function (H3K4me1), and highly conserved elements (HCNEs) ≥50 bp from the following pair-wise comparisons: mouse, opossum and chicken (≥95% identity, black bars); stickleback, medaka, zebrafish and tetraodon (≥70% identity, gray bars; ≥80% identity, black bars). The human versus mouse HNCE density curves were calculated as the number of bases in HCNEs in sliding windows of 150 kb, and colored yellow, orange and red (≥95%, ≥98% and 100% identity, respectively). The co-ordinates are for the human genome (hg18). bp, base pair; chr, chromosome; kb, kilobase.