Figure 3.

Phenotypic variation in fras1 and itga8 mutant phenotypes shows fluctuating asymmetry. (A-C’) Facial cartilage skeleton marked by sox9a:GFP expression at 7.5 dpf, region shown is boxed in red in A”. Compared to wild type (A), the itga8^b1161 mutant skeleton is often asymmetric (B, C). For instance, the fish in (B) shows an extended symplectic cartilage fused to the ceratohyal cartilage on the right side and an unfused, severely shortened, symplectic phenotype on its left side (B’). In another example, both “Short Sy” and “Fused Sy-Ch” symplectic phenotypes (C) are found in a fish presenting only subtle defects on the opposite side (C’). (D, E) At 7.5 dpf, average symplectic length in itga8 mutants is shorter than wild type, but comparable to fras1 mutants. Symplectic cartilages in itga8 mutants show asymmetry similar to fras1 mutants, which is twice as high as wild-type asymmetry. (E) Plot of symplectic lengths measured on left and right sides, with grouped 95% density ellipses. Symplectic lengths for wild types were along the diagonal as expected for a high degree of left/right correlation, but for itga8^b1161 and fras1^b1048 mutants, symplectics were much shorter and do not correlate well between sides. Scale bar (A) is 100 μm, applicable to A-C’. Error bars (D) show 95% confidence intervals: 1.95 times standard error.