The increase in otic tissue, following a heat shock at late gastrulation stages of transgenic hsp:fgf8 embryos, is transient. (A, D) At 28 hours post fertilization, otic vesicles in transgenic fish heat shocked at late gastrulation stages are still larger than in non-transgenic siblings. (B, C, E, F) The size difference of otic vesicles in transgenic and non-transgenic embryos is less prominent at 50 hours post fertilization, and indistinguishable by 72 hours post fertilization. Lateral views of live otic vesicles with anterior to the left and dorsal towards the top. o, otolith. Scale bar: 120 μm.