“…From this time and until the late 1960s, almost all research on S. rimosus genetics concentrated on the following four areas: (i) isolation of nutritional and non-OTC-producing mutants, (ii) classification of the latter using the principle of cosynthesis on solid media, (iii) development of mapping procedures by selective and heteroclone analysis, and (iv) establishment of linkage between mutations by conjugation (6,14,15,17,32,33,54,67,155,156,157,159). During this initial period, interspecific recombination among tetracycline-producing streptomycetes, as well as recombination with some more distantly related species, was also reported (5,11,187).…”