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Figure 6 | BMC Molecular Biology

Figure 6

From: Chromosomal duplications and cointegrates generated by the bacteriophage lamdba Red system in Escherichia coli K-12

Figure 6

Model for Lac+ recombinant formation in linear DNA-by-chromosome crosses. (a) Recombination between the B sequence segments generates two broken chromosome arms. In the diagram, which is not to scale, I, II, and III designate the cryptic prophage tfa homologues ybcX in the DLP12 prophage remnant at 0.58 Mbp in the MG1655 chromosome, a closely linked unnamed pseudogene in the same element, and tfaR in the Rac prophage at 1.43 Mbp, respectively. The lac operon is at 0.36 Mbp. (b) The T segment-ended arm can recombine with any of the three T segments in an unbroken copy of the chromosome, generating a Lac+ chloramphenicol-resistant recombinant. Short arrows indicate the primers used to demonstrate the unique junction formed in the type I recombinant. (c) The recombinant contains two repeated sequence segments, a short one consisting only of the A segment (1.3 kbp), and a long one (0.2 or 1.1 Mbp) consisting of bacterial sequences from B through T.

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