Fig. 2: A decanalizing transgene increases mef2ca mutant phenotype severity.
From: A quadratic paradigm describes the relationship between phenotype severity and variation
a Zebrafish double heterozygous for the mef2cab1086 allele and the fli1:Gal4 transgene were outcrossed to zebrafish heterozygous for the mef2cab1086 allele. Larvae were fixed and stained with Alcian Blue and Alizarin Red at six dpf, genotyped, and the viscerocranium was dissected and flat-mounted. The following structures are labeled in the fli1:Gal4 negative wild type: opercle bone (op), branchiostegal ray (br), symplectic (sy), ceratohyal (ch), and Meckel’s (Mc) cartilages. The symplectic cartilage is outlined with a white dashed line in all individuals. Phenotypes associated with mef2ca mutations are indicated as follows: ectopic opercle bone (arrowhead), shortened symplectic (red arrow), dysmorphic ceratohyal (arrow), reduced Meckel’s cartilage (double arrowhead), interhyal and jaw-joint fusions (^). Scale bar is 100 μm. b Total symplectic cartilage length was measured in six dpf larvae for all mef2ca mutant alleles, then plotted by mef2ca genotype and presence or absence of the fli1:Gal4 transgene. Asterisks indicate significant differences in symplectic cartilage length between genotypes. The p-values from a two-sided Dunnett T3 test are indicated (*≤0.05, **≤0.01, ***≤0.001, ****≤0.0001). Some significance indications are omitted for clarity, for example, all homozygous mutants were significantly different from all wild types and all heterozygotes (p-value < 0.0001). For all p-values comparing all conditions, see Supplementary Table 3. c Symplectic cartilage length on the left and right sides of 6 dpf zebrafish was measured to determine asymmetry or the absolute difference between left and right. The left-right asymmetry is plotted by mef2ca genotype and presence or absence of the fli1:Gal4 transgene. The p-values from a two-sided Dunnett T3 test are indicated (*≤0.05, **≤0.01, ***≤0.001, ****≤0.0001, exact p-values are presented in Supplementary Table 3). In box and whisker plots, the box covers the 25th to 75th quartiles, the line is at the median, and whiskers extend to the minimum and maximum values. The following n numbers represent biological replicates (individual animals) for (b) and (c): b1086; +/+Tg- 15, +/-Tg- 34, -/-Tg- 34, +/+Tg+ 28, +/-Tg+ 44, -/-Tg+ 28. co3008; +/+Tg- 29, +/-Tg- 41, -/-Tg- 30, +/+Tg+ 25, +/-Tg+ 49, -/-Tg+ 32. b631; +/+Tg- 25, +/-Tg- 30, -/-Tg- 28, +/+Tg+ 31, +/-Tg+ 30, -/-Tg+ 24. Source data are provided as a Source Data file.
