Monstrous Tetrahymena with intraclonal variation in structure produced by hereditary modification of normal cells

Monstrous Tetrahymena pyriformis strain GL may be isolated after exposure of normal cells to numerous heat shocks, to flattening on agar or gelatin plates, or to viscous solutions of methyl cellouse. It is shown that in some cases the abnormalities are inherited and that this results in clones where the cells are different from each other and have various abnormalities with respect to cortical pattern, swimming and feeding behavior, and generation time. Furthermore, it is shown that these cells are produced rather than selected by the experimental treatments. Evidence is presented that growth without division is important for production of the abnormal organisms. The basis of the inheritance of the abnormalities is discussed.