Fig. 1. sma-9 mutations cause a loss of dorsal, and duplication of ventral, M lineage descendants. (A-D) Wild-type (A,C) and sma-9(cc604) (B,D) animals at the L2 (A-B) and adult stage (C-D). Blue arrows: SMs labeled with hlh-8::gfp. Red arrowheads: M-derived CCs labeled with intrinsic CC::gfp. C. elegans also contains four embryonically derived CCs located in the anterior half of the animal (labeled by CC::gfp). Blue arrowheads indicate VM1s (descendants of SMs) labeled with egl-15::gfp. Asterisks indicate the position of the vulva. All images were taken at the same magnification and are lateral views of the animal with anterior towards the left and dorsal upwards. Two SMs (one out of focus) and two M-derived CCs are present in wild type (A,C); four SMs (B) and extra SM descendants (D) are present in sma-9(cc604) but there is a lack of M-derived CCs (B,D). sma-9(cc604) animals (B,D) are smaller than wild-type animals (A,C) at the corresponding stages. (E,F) Schematic representation of the wild-type (E) and sma-9 (F) M lineages. The corresponding stages referred to in the paper are indicated on the right of E. Open circles indicate uterine muscles; filled circles indicate vulval muscles. Lines with no designation indicate bodywall muscles.