FIG. 4.

Adult homozygous thrab 1-bp insertion (m/m) mutant fish exhibit hypoplastic epidermis and aplastic musculatures. (A) Representative images of WT fish (a) and homozygous thrab 1-bp insertion (m/m) mutant fish (b) with arrows marking the thin and red belly (denoted as “red belly”). (B) Histology features of hematoxylin and eosin stained adult skin on the belly of WT female (a) and male (c) fish, and female homozygous thrab 1-bp insertion (m/m) mutant fish (b) and male (d) fish (10 × objective). The arrow heads point to epidermis. Homozygous thrab 1-bp insertion (m/m) mutant fish of both sexes show very thin epidermis, lack of scales, and a true abdominal wall.