Fig. 6. Hyperactivation of EGL-15 results in multiple M lineage defects. (A) The cell lineage of the M mesoblast. M divides along the dorsoventral axis; the two M.x daughters divide along the left/right axis. The remaining divisions in the lineage are oriented along the anteroposterior axis. d, dorsal; v, ventral; l, left; r, right; a, anterior; p, posterior; bm, body wall muscle; dcc, dorsal coelomocyte; SM, sex myoblast (adapted from Sulston and Horvitz, 1977). (B) The effect of EGL-15 hyperactivation on SM positioning, presence of dorsal coelomocytes and orientation defects in early M lineage cell divisions. SM positions are scored with respect to the hypodermal Pn.p cell metric. SMs in wild-type animals are centered at P6.p, indicated by the arrow; the blue rectangle represents the positions of normal SMs. Each full SM distribution is represented by a box-and-whisker plot, where the box extends over the distribution of the central 50% of the SMs and the line within the box is at the median position. Whiskers extend anteriorly and posteriorly to data points up to 75% of the length of the box. SMs that fall outside the box and whiskers are represented by an individual hash mark (see Material and methods). Red circles indicate dorsally positioned SMs. ayIs16 was used in place of ayIs15 for technical strain construction considerations. A similar survey of SMs in ayIs15 hermaphrodites gave a distribution consistent with that seen for ayIs16. At least 30 SMs were scored for each SM distribution and at least 30 animals were scored for dorsal coelomocyte and M-lineage cell-division defects.