Genetic studies of the pyrimidine permeases from Saccharomyces cerevisiae: lack of intragenic complementation.

A search for intragenic complementation of mutants of the cytosine and uracil permeases of Saccharomyces cerevisiae was made. Among numerous diploid pairs of mutants of the cytosine permease gene no complementation was found. Similarly negative results were obtained with pairs of mutants of the uracil permease. The significance of these results is discussed.