Somitogenesis in a zebrafish embryo, showing somite formation during development of the trunk and tail. Notice the anteroposterior progression of the somitogenesis process, most obvious in the emerging tail. Movie courtesy Andrew Oates.

A zebrafish embryo was immobilized by injection with alpha-bungarotoxin RNA and placement in a lateral embryo array. Images were captured on an upright, brightfield microscope. The movie shows the whole of zebrafish development from zygote to the end of embryogenesis. Cleavage and epiboly precede gastrulation and then axial extension, somitogenesis and the rest of organogenesis. One can see the emergence of pigment in the eye and the epidermis as well as the emergence of the muscles along the length of the tail. Movie courtesy Ian Swinburne and Sean Megason (Harvard Medical School).