Fig 2
Selective breeding just for ectopic bone penetrance modifies penetrance of other mef2ca-associated craniofacial phenotypes to different extents.(A) Wild-type 6 days post fertilization (dpf) zebrafish larvae were stained with Alcian Blue and Alizarin Red to label cartilage and bone then flat mounted and imaged. The following craniofacial skeletal elements are indicated in the micrograph and graphic: opercle bone (op), branchiostegal ray (br), Meckel’s (mc), ceratohyal (ch), symplectic (sy) and hyomandibular (hm) cartilages, interhyal (ih) and jaw (jj) joints. Scale bar: 50 μm. (B, C) Penetrance of most phenotypes associated with mef2ca are reduced in homozygous mutants from the low-penetrance strain compared to homozygous mutants from the high-penetrance strain including: ectopic bone (arrowheads), interhyal- and jaw-joint fusions (^), dysmorphic ch (arrows), reduced mc (double arrowhead). A shortened sy cartilage (red arrows) remains fully penetrant in both strains. (D) Penetrance of mef2ca-associated phenotypes from full-sibling low- and high-penetrance families. Asterisks indicate statistically significant penetrance differences between homozygous mutants in low-penetrance compared with high-penetrance strains (Fisher’s exact test at alpha = 0.05).
|