Fate mapping was developed by Walter Vogt as a means by which to trace the development of specific regions of the early embryo. To do this, Vogt used agar chips impregnated with vital dyes
Vogt used chips of agar impregnated with vital dyes to systematically mark the surface of the embryo at various stages of development. In this case the marks are along a meridonal line. Click the highlighted numbers to see how vital staining was described by Vogt in his original work.