Fig. 7

Fig. 7 Calcitic otolith formation in otop1 morphant fish. (A) Scanning electron microscopy of the otic cavity of a 7 dpf uninjected age-matched control showing a smaller utricular (left) and larger saccular otolith. Both otoliths are rounded and cover the entire sensory maculae. (B) Eight-ng MO-1-injected morphant otic cavity at 7 dpf. Otoliths are angular. The sensory epithelium is visible below the utricular otolith. The morphant otoliths resembled inorganic crystals instead of organic calcification. (C) The 360° rotation image of a single crystal X-ray diffraction of a wild-type 7 dpf otolith. Little prominent diffraction pattern is present, indicating that calcium carbonate aragonite crystallites are arranged in a dustlike mosaic pattern across the surface of the otolith. (D) Single crystal X-ray diffraction of a morphant otolith showing that otoliths similar to those above (B) behave as a single crystal. The unit cell derived from this diffraction pattern was consistent with the calcitic polymorph of calcium carbonate. Scale bar indicates 50 μm.