Figure 7.

Expression of fgfr1 and msxC in regenerating caudal fins of brushtail mutants. Compared to a wildtype platyfish (A), X. maculatus brushtail mutants possess elongated median caudal fin rays (B). Male brushtail mutants also develop a small ventral extension of the caudal fin (swordlet). fgfr1 and msxC show a graded expression pattern in regenerating caudal fins of brushtail mutants at different stages of regeneration with strongest expression in the median fin rays (C-J). fgfr1 (C-F) and msxC (G-J) are expressed in a similar pattern as in X. helleri regenerating caudal fins. At later stages of regeneration, fgfr1 (F) and msxC show stronger expression in the ventral-most caudal fin rays of males compared to females (J). White arrowheads indicate expression in scleroblasts, black arrowheads the msxC expression domain in the distal blastema and white arrows the plain of amputation. (n = 3 for every stage and probe; scale bars: A and B: 1 mm; C-J: 200 μm).