Fig. 3. Possible models by which an unequal pulling force could be generated. (A) The force generated by the pushing apart of the overlapping midzone microtubules is unequal. (B) The force of the pulling astral microtubules is unequal. The microtubules on one side of the cell cortex are either destabilised (red lines in blue area in C) or stabilised (red lines in green area in D). Microtubules are indicated as black lines and centrosomes as filled black circles (see also ^|| footnote on p. 2258).