Plasticity

Definition

Plasticity means first the ability of some organisms to develop into several possible phenotypes depending on the environment they face. For instance, crocodiles with a same genotype will develop either into male or into females depending upon temperature. The phenomenon of plasticity has always been seen as proper to the living things, and was an important keyword in the eighteenth-century vitalism. In the era of genetics, plasticity means a one-to-many mapping between genotype and phenotype.

Second, quite differently it means developmental plasticity, which is the ability of cells and sets of cell to adopt various cell fates in development, according to the inductions they will receive. Sea urchin experiments in around 1,900 demonstrated this ability, first when a sea urchin embryonic cell once divided gave rise to two embryos (Hans Driesch) – which proved that embryonic cell were likely to adopt all fates, that is, were “totipotent,” second, when Spemann and Mangold...