Fig. 4. MyoD expression in herring embryos reared at 8°C. (A) Three-somite embryo; head positioned towards the bottom of the figure. The MyoD transcript accumulates in the adaxial cells prior to expanding into the lateral posterior regions of newly formed somites. (B–G) 15-somite herring embryo; (B–E) transverse sections, arranged most posterior first, showing the accumulation of MyoD transcript in (B) the adaxial cells only and (C–E) the adaxial cells and the somites. (F,G) Sagittal sections, head towards the top of the figure, showing the accumulation of MyoD transcript in the somites and (G) in the adaxial cells of the presomitic mesoderm. n, notochord; pm, presomitic mesoderm. Arrows indicate adaxial cells; arrowheads indicate somites. Scale bars, 50 µm.
