Increase in conjugational transmission frequency of nonconjugative plasmids.

Addition of Eco RI fragment 6 of the Escherichia coli sex factor F to pSC101 increases the frequency of its transmission by RI-19 and ColVB. Transmission frequencies of pSC101 and two pSC101 chimeras are also increased after the putative transposition of drug resistance element Tn3 from RI-19. These increases may result from addition of an origin of conjugatinal transfer to the plasmids.