Fig. 7. Effects of Raf clones on twist expression. twi and ftz protein distribution in gastrulating embryos. All embryos are shown from the ventral side. Anterior is towards the left. (A) Embryo showing normal twi expression. The twi-expressing cells invaginate along the ventral midline (ventral furrow). The embryo is derived from an egg collection in which the eggs carried several Raf clones, ranging from 2-16 cells in size. (B-E) Embryos derived from eggs carrying clones with an average size of 30-60 cells. (B,C) The ventral furrow is displaced to lateral positions as it runs along the AP axis. (D,E) Local expansions of the twi domain are accompanied by a bifurcation of the ventral furrow. In some embryos, similar effects were also seen at more posterior positions.