Fig. 2

Tracing cell fate by labelling with lysinated rhodamine dextran (LRDX). In this example, a single cell injected with LRDX at the anterior site of delta gene expression in an early otocyst (18 hpf; A) ends up in the anteroventral macula, where it gives rise to a hair cell plus a supporting cell (identified by their shape and location in the epithelium; B and C). The pictures are superpositions of fluorescence and transmission-optics images taken with a confocal microscope in the living embryo at the time of injection and 24 and 48 hours afterwards. The specimen shown is one of approximately 80 that were used to build up a fate map (Haddon, 1997). In other specimens, labelled cells at the same original site end up in the same location. ao, anterior otolith; po, posterior otolith; am, anterior macula; hc, hair cell.