Fig. 5. Genetic mosaics of C. elegans implicate hyp7 as the focus of tsp-15 activity. A total of 28 mosaics were identified that had had early losses of mnEx140 but displayed no aspects of the sv15 mutant phenotype, indicating where in the early cell lineage inheritance of wild-type tsp-15 DNA is sufficient to prevent the mutant phenotype. Based on expression of sur-5::gfp in descendents of the early cells of an embryo (Sulston et al., 1983), cells establishing a positive clone in an individual mosaic are indicated with a square next to the name of the cell. For two mosaics, one depicted with circles and the other with diamonds, two cells of the embryo independently established positive clones. The early cells of an embryo that contribute to the hyp7 syncytium are indicated.