Figure 1.

Modes of asymmetric cell division. (A) Asymmetric cell fate specification is regulated by a niche-derived signal. Cells that contact the niche retain their identity, whereas cells that become detached from the niche after division adopt a different cell fate. (B) External polarity induces the asymmetric localization of cell fate determinants (green). (C) Intrinsic asymmetry localizes polarity proteins (red), which instruct cell fate determinants (green) to segregate asymmetrically during mitosis in the absence of extracellular cues (DNA, blue).