Fred Heffron

TL;DR: Genetic data suggest that Tn3 contains a third site (Gill et al., 1978), designated IRS (internal resolution site), whose absence results in the insertion of two complete copies of Tn2 as direct repeats into the recipient DNA, and that the IRS site is required for recombination and subsequent segregation of the direct repeats to leave a single copy of TN3.

TL;DR: Restriction endonuclease subclones of the Escherichia coli gene encoding the heat stable (ST) toxin exhibit a stem and loop structure similar to those seen in many procaryotic transposons, and restriction and DNA sequence data strongly suggest that the ST transposon, Tn1681, is flanked by inverted repeats of IS1.

TL;DR: A method for mutagenizing circular DNA molecules has been developed that uses synthetic oligodeoxynucleotide restriction sites as mutagens, and has been used to produce a fine-structure map of RSF1050, 60% of which is a transposable DNA sequence encoding the TEM beta-lactamase.

TL;DR: The sequence of the methotrexate-resistant dihydrofolate reductase (DHFR) gene borne by the plasmid R-388 was determined by an in vitro mutagenesis method involving insertion of synthetic oligonucleotide decamers encoding the BamHI recognition site.

TL;DR: A recently developed method for detecting transposition was employed to genetically "label" conjugative plasmids such as F and Ent P307, which do not normally exhibit a readily identifiable phenotype.