Red adenine-dependent mutants of Hansenula polymorpha, Pichia guilliermondii, Williopsis saturnus yeasts have been transformed by the plasmid pYE (ADE2) 2 DNA containing ADE2 gene from Saccharomyces cerevisiae. The analysis of two P. guilliermondii Ade+-transformants has revealed the integration of pYE (ADE2)2 sequence into the recipient strain genome and partial restoration of the deficient function.