Fig. 5

Wild-type, her1^-/- and her7^-/- fish form almost identical numbers of vertebrae. Wild-type (A), her1^-/- (B) and her7^-/- (C) fish stained with calcein to visualise calcified tissues. These fish are 21-28 days old and measure 10-12 mm from head to tail. Most her7^-/- fish have skeletal abnormalities affecting their posterior skeleton, such as missing or bifurcated ribs, irregularly sized vertebrae, and malformation and/or misalignment of the neural and haemal spines. her1^-/- fish rarely have posterior skeletal defects, but often exhibit defects in their anterior vertebrae (e.g. an extra Weberian vertebra, not visible in this specimen). Mean vertebra counts are the same within 3% for the three genotypes (see Table 1).