Homology Between the Deoxyribonucleic Acids of Haemophilus influenzae and Haemophilus parainfluenzae

To determine the degree of homology between deoxyribonucleic acid (DNA) from Haemophilus influenzae and that from Haemophilus parainfluenzae, the two DNAs were hybridized by the membrane-filter technique. It was found that 44% of the DNA from each species was sufficiently homologous to allow hybrid formation.