Fig. 3. perd and Grip have similar phenotypes and are coexpressed. (A-C) The terminal muscle phenotype in Grip mutant embryos (C) appears similar to, although less severe than, the perd phenotype (B). (D-F) The time course of development of the Grip phenotype is very similar to that of perd (compare with Fig. 2). (G-I) Simultaneous detection of perd RNA (G) and Grip RNA (H) by fluorescence in situ hybridization shows that many cells coexpress both genes (arrowheads). (J,K) Quantification of muscle VL1 phenotypes in perd (J) and Grip (K) mutant embryos at three different stages of development. Each mutation causes a majority of muscles to appear abnormal in the earliest phases of process extension, but most muscles recover and achieve an appropriate morphology at later stages in the Grip mutant, whereas the perd mutant phenotype is increasingly severe. In addition, a small number of muscles with misdirected projections can be observed at stage 15 in both genotypes (yellow).