Figure 3

Cleavage behavior after cell elimination in  P. sambesii  . (a-c) After ablation of P1, the S1 descendants divide and form a blastocoel (marked with asterisk); (d, e) after ablation of P1, the S1 descendants can express normal synchronous cell cycles (d) or S1p descendants cleave asynchronously (e); (f-m) after early P2 ablation, S2 descendants lose their ability for asynchronous cell cycles (m) but after late ablation the normal cell cycle differences are expressed (l); (i-k) not after early (j) but after late extrusion of P2 (i), fluorescent marker dye accumulates in the gut primordium (k); (n-q) after early ablation of S3 (or P1/P2, see text), the typical retardation of cell cycles in three S1 descendants (see Figure 6) is lost (q). a-i, n-p: DIC optics; j, k, epifluorescence. Bar, 10 μm.