Zac1+m/- retinae develop an ectopic amacrine cell layer and supernumerary rod photoreceptors. (a-h) E18.5→8DIV retinal explants. DAPI-stained (a) wild-type and (b) Zac1+m/- explants. Rhodopsin expression in (c) wild-type and (d) Zac1+m/-+ ECL retinae. (e,e',f,f') Pax6 and (g,g',h,h') syntaxin expression in amacrine cells in wild-type (e,e',g,g') and Zac1+m/-+ECL (f,f',h,h') retinae. Asterisks mark the ECL. The duplicated IPL is labeled by ipl' in (h'). Blue is DAPI counterstain. (i) Average of the absolute number of DAPI+ nuclei/layer in a standard counting field in wild-type (black bar; total DAPI+ nuclei counted in 30 fields; ONL: 23,700; INL: 9,870; GCL: 1,776), Zac1+m/- without an ECL (grey bar; total DAPI+ nuclei counted in 9 fields; ONL: 6,615; INL: 2,826; GCL: 498 nuclei) and Zac1+m/-+ECL (white bar; total DAPI+ nuclei counted in 27 fields; ONL: 26,175; INL: 11,968; GCL: 1,674). (j) Percentage of each retinal cell type based on total cell counts in wild-type (black bar; HC: 56 calbindin+/7,183 DAPI+; AC: 1,832 Pax6+/11,696 DAPI+; BP: 819 Chx10+/9,302 DAPI+; MG: 1,003 p27+/18,465 DAPI+ nuclei; 537 CRALBP+/9,169 DAPI+), Zac1+m/- without an ECL (grey bar; HC: 64 calbindin+/12,960 DAPI+; AC: 1,558 Pax6+/10,304 DAPI+; BP: 1,077 Chx10+/10,171 DAPI+; MG: 430 p27+/9,966 DAPI+; 332 CRALBP+/6,773 DAPI+) and Zac1+m/-+ECL retinae (white bar; HC: 11 calbindin+/1,924 DAPI+; AC: 2,068 Pax6+/11,302 DAPI+; BP: 646 Chx10+/9,157 DAPI+; MG: 395 p27+/9,921 DAPI+; 240 CRALBP+/3,319 DAPI+). AC, amacrine cell; BP, bipolar cell; HC, horizontal cell; MG, Müller glia.