Learn More
Molecular methods are used widely to measure genetic diversity within populations and determine relationships among species. However, it is difficult to observe genomic evolution in action because these dynamics are too slow in most organisms. To overcome this limitation, we sampled genomes from populations of Escherichia coli evolving in the laboratory for(More)
The Escherichia coli resident mobile element IS30 has pronounced target specificity. Upon transposition, the element frequently inserts exactly into the same position of a preferred target sequence. Insertion sites in phages, plasmids and in the genome of E. coli are characterized by an exceptionally long palindromic consensus sequence that provides strong(More)
Plasmids carrying two IS30 elements in the same orientation, as in the composite transposon Tn2706, are structurally unstable in Escherichia coli. A primary segregation product is formed by site-specific deletion of the sequences carried between the two IS30 elements. The resulting covalently closed replicon carries the two IS30 elements as tandem repeats(More)
In the present study, we demonstrate that the terminal inverted repeats of the Escherichia coli insertion sequence IS30 are functional target sites for the transposition of the (IS30)2 dimer, which represents an intermediate structure in the transposition of IS30. Comparative analysis of various target regions revealed that the left and right ends differ in(More)
The gene for the insertion sequence (IS) 30 transposase is placed under the control of the tac promoter, and large quantities of transposase are expressed upon induction. The resulting protein precipitates inside the Escherichia coli cells in the form of inclusion bodies which, upon cell lysis, cannot be dissolved under nondenaturing conditions. In(More)
Target duplication during transposition is one of the characteristics of mobile genetic elements. IS1, a resident insertion element of Escherichia coli K-12, was known to generate a 9-base-pair target duplication, while an IS1 variant, characterized by a nucleotide substitution in one of its terminal inverted repeats, was reported to duplicate 8 base pairs(More)
Bacterial subclones recovered from an old stab culture of Escherichia coli K-12 revealed a high degree of genetic diversity, which occurred in spite of a very reduced rate of propagation during storage. This conclusion is based on a pronounced restriction fragment length polymorphism (RFLP) detected upon hybridization with internal fragments of eight(More)
Escherichia coli pel- mutants inhibit the penetration of bacteriophage lambda DNA into the cell. Using P1 mediated cotransduction, we mapped pel- mutations between markers fadD and eda in the interval of minute 40 of the revised E. coli K-12 map. This places pel in the same region as genes kdgR and ptsM. Mutations in kdgR usually do not alter the Pel(More)