Cellular Segregation and Heterocytic Dominance in Hydra

Hydra heterocytes-that is, hydra containing cells from both normal and mutant animals, were used for studying some developmental properties of mixed cell populations. Cells which initially had originated from a nonbudding mutant, and which subsequently became part of a heterocyte of normal appearance, were able to proliferate, to segregate, to come off as buds, and to express their phenotype in those buds. Furthermore, the heterocytes underwent a transformation in which the mutant phenotype eventually became dominant in all instances.