A Case of Limitation of Phenotypic Variation

Abstract

JINKS¹ suggests that where phenotypic variation is caused by a cytoplasmic system, the range of phenotypic expression attainable by the system would have quite definite limits imposed by the system itself (cytoplasmic limits) or, by the non-viability of phenotypes lying outside these limits (physiological limits). Cytoplasmic limits would result where further changes in cytoplasmic content are impossible, as when all cytoplasmic elements involved in the change are lost. Physiological limits would result where although more extreme changes in the cytoplasm are possible they would lead only to non-viable phenotypes. Jinks's results suggested a physiological basis to limits of variation obtained in Aspergillus glaucus.