Extended Data Figure 5. Phenotype of adult hox13 mutant fish.

a, c, e, g, i, k, m. Whole body morphology of hox13 deletion mutants were photographed at four months old; hoxa13a^-/- (8 bp del. / 29 bp del.), hoxa13b^-/- (4bp del. / 13 bp ins.), hoxd13a^-/- (5 bp ins. / 10 bp ins.), hoxa13a^-/-, hoxa13b^-/- double homozygous fish (8 bp del. / 29 bp del., 13bp ins. / 13 bp ins.) and triple knockout (k, m. mosaic for hoxa13b and hoxd13a) fish (Methods). n = 3 fish for wild-type, single and double mutants and n = 5 fish for triple mosaic mutants (same specimens were used as Figure 3). The detail of mutant sequence is summarized in Extended Data Table 3. Each single homozygous mutant fish shows normal morphology at four months old except for slightly short pectoral fin rays of hoxa13a^-/- or a13b^-/- single mutant. Hoxa13a^-/-, hoxa13b^-/- double homozygous fish shows a severe reduction of fin rays in pectoral, pelvic, dorsal and anal fins compared with wild-type. The triple knockout (mosaic for hoxa13b and hoxd13a) fish also showed the reduction of fin rays. Scale bar is 5 mm. Due to the size of the adult fish, three different pictures for anterior, center and posterior of the body were merged to make whole body pictures. b, d, f, h, j, l, n, Bone staining pictures of mutant fish. The endochondral bones of pectoral fins are shown. Whereas single homozygous fish show relatively normal proximal radials (b, d, f, h, Figure 3), double homozygous mutants show fused third and fourth proximal radials (j). One of triple knockout (mosaic for hoxa13b and hoxd13a, 0, 25, 50 %) fish show fused third and fourth proximal radials (i), but another triple knockout (0, 0, 0 %) show more broken down proximal radials (n). n = 3 fish for wild-type, single and double mutants and n = 5 fish for triple mosaic mutants (same specimens were used as Figure 3). The scale bar is 500 μm. o, p, Examples of counting distal radials in wild-type and hoxa13a^-/-, hoxa13b^-/- double homozygous fish. First distal radials are not shown in CT segmentation because of a fusion with first fin ray. q, The number variation of distal radial in mutant fish. Multiple fins were investigated in wild-type (25 fish / 50 fins), hoxa13a^-/- (4 bp del. / 4 bp del., three fish / 6 fins), hoxa13b^-/- (4 bp del. / 13 bp ins., three fish / 6 fins), hoxd13a^-/- (5 bp ins. / 17 bp del., three fish / 6 fins), hoxa13a^-/-, hoxa13b^-/- double homozygous (8 bp del. / 29 bp del., 13 bp ins. / 13 bp ins., three fish / 6 fins) and triple knockout (mosaic for hoxa13b and hoxd13a) fish (five fish / 10 fins). The number of distal radials increased to 10 to 13 in double and triple mutants. The difference of distal radial number between wild-type and double homozygous or wild-type and triple knockout (mosaic for hoxa13b and hoxd13a) is statistically significant (p= 0.0014 or p = 0.00001 by compare means t-test, two-tailed distribution).