The lineages of individual cells of the Xenopus cleavage-stage embryo have been fate-mapped to reveal the subset of blastomeres that are the major and minor precursors of the retina. Using this retina fate map, one can test the commitment of each of these cells to various retinal cell fates by manipulating the environment in which they develop. This chapter presents the techniques for identifying specific retina blastomere precursor cells, deleting them to test whether they are required for producing specific kinds of retinal cells, transplanting them to novel embryonic locations in host embryos to test whether they are committed to produce specific kinds of retinal cells, and growing them in explant culture to determine if their ability to produce specific kinds of retinal cells is autonomous.