[Physiological polymorphism of grass frog populations. IV. Effect of stress on the phenotypic expression of population polymorphism judged by the level of heat resistance of muscle tissue].

A study was made on the polymorphism of the population of Rana temporaria by the heat resistance of muscle tissue. Stress resulted in the elimination of group differences in the heat resistance of muscles. Thus, the phenotypical response of individuals to stress is masking the genotypical heterogeneity of the population judged from the heat resistance of muscle tissue.