Fig. 2. retn mutations affect viability. (A) Eclosion rates for retn heteroallelic combinations. retn^z2-428/retn^dri2 (1) and retn^z2-428/retn^dri1 (2) offspring eclose with 8% and 25% of expected rates; retn^RU50/retn^dri2 (3) and retn^RU50/retn^dri1 (4) eclose with 65% and 68% of expected numbers; retn^z2-428/retn^dri8 (5) and retn^RU50/retn^dri8 (6) eclose with 71% and 100% of expected numbers. retn^z2-428/retn^RU50 (7) is completely viable. (B) retn cDNA rescues partial lethality of retn-Gal4/retn^z2-428. retn-Gal4⁸⁹/retn^z2-428; +/+ trans-heterozygotes (1) eclose with 33% of expected numbers, while retn-Gal4⁸⁹/retn^z2-428; UAS-retn/+ individuals (2) eclose at 100% of expected rates.