Partial Reassociation Between the Deoxyribonucleic Acids of Neisseria lactamicus and Neisseria meningitidis.

The similarity in polynucleotide sequence of seven strains of Neisseria lactamicus to N. meningitidis and to each other was investigated. The per cent reassociation between single-stranded N. lactamicus deoxyribonucleic acid (DNA), immobilized on membrane filters, with labeled single-stranded DNA fragments derived from strain SD-6 (group C) of N. meningitidis varied from 75 to 56. With strain ATCC 23972 of N. lactamicus furnishing the labeled DNA fragments, reassociation was 72% with N. meningitidis, 31% with N. subflava, and 98 to 72% with the other strains of N. lactamicus. It is concluded that on the basis of DNA reassociation N. lactamicus can be distinguished from N. meningitidis and N. subflava, but constitutes a relatively heterogeneous species.