Cell lineage analysis and mosaic analysis of mutations are important techniques that are used to study the development of many organisms. Unfortunately, the methods employed for such analyses are usually inefficient, technically demanding or labor intensive. In Drosophila, the most common methodology used for the generation of mosaic animals is mitotic recombination, which is induced by X-rays. Although this technique is simple, it has the undesirable characteristics of a low efficiency and a high rate of cell death. Furthermore, although a large number of marker systems has been employed to detect mitotic recombinants, none allows easy identification of clones for all cell types.