Two new types of Hemophilus influenzae, Sab and Sad have been produced in vitro. Each exhibits the presence of the type specific polysaccharides of 2 types of E. influenzae within the same cell. In Sab the polysaccharides of types a and b have been demonstrated and in Sad those which characterize types a and d. The Sab and Sad traits are inherited.
Sab was produced by the action of DNA-containing extract isolated from type a on either type b cells or Rb cells (non-encapsulated non-type-specific cells derived from type b). Sad cells were formed as a result of the action of the DNA-containing extract isolated from type d on cells intermediate between Rab and Sab cells.
DNA-containing extracts isolated from Sab cells have induced the Sab trait in Rd cells with predictable regularity.
Evidence has been presented that the hereditary determinant of Sab cells is a new genetic substance with new functions. Therefore, the interaction of the DNA-containing substance from cells of one genetic type with living cells of a genetically different type has produced what appears to be a new individual which differs from each of the cells contributing the differing genetic traits but has at least one trait in common with each.
Sab cells derived presumably from a single cell show the appearance of type b cells sometime during the first 7 generations.
