Evidence that either strand of DNA can transform

Abstract

Transformation in Hemophilus influenzae occurs by the incorporation of a single strand of donor DNA into the recipient chromosome. The question arises whether this incorporation involves one unique strand or either strand, of the donor DNA molecule. The problem was investigated by following the transforming activity of the recipient strand associated with the donor DNA as a function of growth of the transforming cells. Before replication, only the donor strand contained transforming activity; but after one generation time, both strands carried the genetic information. It was concluded that either strand of DNA can transform.