Have you ever wondered how individual fingers form? If you have taken a developmental biology class, you know that the hand first develops as a mitten-like structure with the future fingers connected (Figure 1). Later, during normal development, the cells in the areas between the fingers undergo programmed cell death, and thus leave behind five fingers on each hand. Programmed cell death is important not only in development and long term viability of animals, but also plays a role in unicellular organisms. For example, in the social amoeba Dictyostelium, a subset of cells undergoes a type of programmed cell death similar to autophagy to form fruiting body stalks. The remaining dead cells in the stalk are highly vacuolated and provide support for the spore body.
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