Fig. 6

gdf6a modulates tbx2b regulation of UV cone and rod development.

A, B. When [gdf6a^+/s327;tbx2b^+/lor] compound heterozygous mutants are in-crossed (inx), a disproportionate fraction of microphthalmic offspring exhibit the lots-of-rods phenotype compared to normophthalmic siblings, tbx2b^+/lor in-crosses, and to predicted Mendelian ratios of the recessive lots-of-rods phenotype (X² ***p<0.001; 3 replicates of n = 17, 19, 35 microphthalmics; 6dpf). UV cones and rods were labeled using antibodies 10C9.1 and 4C12 displayed in magenta and green, respectively. A portion of microphthalmic larvae with the lots-of-rods phenotype has a tbx2b^+/lor genotype (see Table 1). C, D. When [gdf6a^+/s327;tbx2b^+/fby] compound heterozygous mutants are in- crossed, the lots-of-rods phenotype is again observed at higher rates in microphthlamic eyes compared to normophthalmic eyes (X² *p = 0.007; 1 replicate, n = 39 microphthalmics, 6 dpf). Panel D shows rod opsin in situ hybridization (red). Scale bars are all 50 μm. E. Genotyping for the lor mutation was performed via linkage analysis using an A/T synonymous SNP located before the DNA binding domain of tbx2b in lor and non-lor alleles, respectively. gdf6a^s327/s327 mutants with a corresponding SNP of T were used in crossing of the mutant lines.