Examples of a change in endogenous gene expression associated to different enhancer activities in mouse and zebrafish. A) Expression driven by the Hs382 enhancer is detected in DRG (arrow) in mouse. B) This expression is coincident with the Hs382 target gene, Znf536 (arrow). C) In zebrafish, the Hs382 enhancer does not drive expression in DRGs (arrow). This contrasts with a positive control for DRG expression (inset, arrow; Tg(−3.1neurog1:GFP)sb2). D) This absence coincides with lack of expression of Znf536 in DRG (arrow).