(A) Lateral views of control fish and age-matched urp1∆P;urp2∆P mutants. Arrows point to forming body curves. (B) Traces of body shape every 2 days for 5 fish per time point from 3 to 17 dpf. (C) Growth curves for control and urp1∆P;urp2∆P mutants were indistinguishable. Arrow shows time of curve onset. Mean ± s.d. is plotted. (D) Microcomputed tomography (µCT) reconstitutions of spines at 1 mpf with heads, fins, and ribs digitally removed. Scale bar: 1 mm. (E) µCT reconstitutions of three pre-caudal and two caudal vertebrae including frontal and lateral views of the highlighted vertebra. No major structural defects such as fusions were observed in urp1∆P;urp2∆P mutants. (F) Vertebral body rostral-caudal length (L1/L2) and dorsal-ventral height (H1/H2) aspect ratios for six vertebrae of wild type (n=4) and urp1∆P;urp2∆P mutants (n=4). Length aspect ratios were significantly more variable in mutants, but height aspect ratios were unchanged (p=0.022 and 0.745, respectively, Bartlett’s test for equal variances). (G) Calcein staining revealed well-structured vertebrae forming in control (standard length 5.7 mm) and urp1∆P;urp2∆P mutant (standard length 5.7 mm) fish. n>30 fish per condition.
