Fig. 1. Constructs used to generate transgenic animals. (A-D) The reporter transgene was inserted into the first exon of the zebrafish hoxb5a (A) or hoxb5b (C) gene. (B) The J3 element was deleted from the hoxb5a construct. (D) J3 was inserted into the hoxb5b construct. (E-G) Individual conserved non-coding elements (CNEs) from mouse and zebrafish Hoxb5 loci were coupled to a β-globin minimal promoter and the EGFP or lacZ reporter genes (black rectangles). a and b represent the hoxba and hoxbb zebrafish complexes, respectively. In A-D, hatched rectangles indicate exon sequences; black triangles, loxP sites; amp, ampicillin resistance gene; neo, neomycin resistance gene. Mm, Mus musculus; Dr, Danio rerio.