Fig. 5. Mesoderm spreading is initiated in the absence of MAPK activation. Cross sections of embryos stained for Twist to reveal the development of the mesoderm (brown). (A) A wild-type embryo. (B) A homozygous dof¹ mutant embryo. (C-F) Mesoderm development in embryos derived from germline mutant clones lacking both the maternal and zygotic function of (C) Dsor1^LH110, (D) Ras85D^c40B, (E) csw^E(sev)1A-eOP and (F) dShc^13G.