Genetic analysis of intraspecies recombinant formation by protoplast fusion with three species ofStreptomyces

Abstract

Abstract Protoplast fusion was shown to produce high frequencies of recombinant progeny in intraspecies crosses with auxotrophic mutants of Streptomyces canescens, Streptomyces griseus and Streptomyces limosus . The fused protoplasts were regenerated on non-selective media and the progeny spores subsequently analysed on selective media to allow detection of all possible genotypes. Prototrophic recombinants arose with frequencies of between 1% and 8%. All 4 possible genotypes were recovered in a series of 2-factor crosses and 6 of the 8 possible genotypes were detected in a 3-factor cross. In spite of attempts to equalise the ratios of parental protoplasts in the fusion mixture, there were noticeable deviations from unity in the ratios of parental genotypes in the progeny.