Fig. 4

Posterior enlargement of the swim bladder in hoxaa cluster-deleted mutants with an additional pair of pleural ribs. (a–f) Micro-CT scan images showing the swim bladder (red) and the surrounding skeletal structures in wild-type (n = 4) and hoxaa cluster-deleted adult fish (n = 4). To ensure reproducibility, two representative images are shown for hoxaa cluster-deleted adult fish. The vertebrae are numbered in order starting from the first rib-bearing vertebra. To facilitate comparisons, the dimensions of the fish body were standardized based on the distance between the first and ninth rib-bearing vertebra, shown by the yellow dashed line. The blue dashed line indicates the posterior extent of the swim bladder in wild-type fish, while the light blue dashed lines represent the posterior extent of the swim bladder in hoxaa cluster-deficient mutants. A 3D movie is available as Movie S11. (g) A comparison of the maximum Feret diameter of the anterior and posterior lobes between wild-type and hoxaa cluster-deficient mutants. A Student's t-test was performed, with significance indicated as *p < 0.05 and ***p < 0.001. Scale bars: 1000 μm.