Electrophoretic analysis of Euplotes crassus stocks from populations differing in their breeding systems

Abstract

Stocks of sympatric autogamous (A+) and nonautogamous (A−) populations of the ciliate Euplotes crassus have been analysed using sodium dodecyl sulfate – polyacrylamide gel electrophoresis. These stocks differ markedly in the protein contents of their particulate cell fractions. The results agree with breeding tests and studies on the physiological tolerance to various stresses in suggesting some degree of genetic differentiation between A+ and A− stocks. A plausible hypothesis is that they constitute separate "subspecies" within the same morphological species E. crassus.