Implementation and extension of MacWilliams model for pre-stalk pre-spore regulation in cellular slime mold

Various versions are formulated and discussed of a model suggested by MacWilliams for pre-stalk pre-spore differentiation in cellular slime mold. Development of the model yields maturation, an increasing irreversibility of the differentiation. Regeneration of the original pattern after amputation is obtained by a modification of the mechanism for maturation. The detailed workings of this mechanism are followed by means of a modified phase-plane diagram. The final model is placed in an evolutionary perspective and is compared with other models. Several experiments are suggested.