Interrelation of Nocardia asteroides and Related Taxa as Indicated by Deoxyribonucleic Acid Reassociation

The degree of binding was determined between deoxyribonucleic acid (DNA) preparations from nocardias and uracil-labeled DNA from four reference strains of Nocardia asteroides. The N. asteroides strains fell into three DNA homology groups, one of which contained the type strain of Nocardia farcinica ATCC 3318. The relevance of the genetic data to the structure of the N. asteroides taxon is discussed. The nucleotide composition of the DNA preparations from the N. asteroides strains fell between 64 and 68 mol% guanine plus cytosine.