[Homologous recombination and chromosomal rearrangements in Escherichia coli strains carrying a heterozygous tandem duplication].
Heterozygous tandem duplications formed in conjugational matings in Escherichia coli provides a convenient model system for studying the evolution of bacterial chromosome. Heterozygous duplications segregate various classes of haploid and diploid recombinants that appear as a result of unequal crossing over between sister chromosomes. In this work, an extended tandem duplication in the deo operon of E. coli carrying deoA deoB::Tn5/deoC deoD thr::Tn9 alleles was examined. Recombination between homologous DNA repeats in the duplication was studied in strains carrying different combinations of recBC, sbcBC, recB::Tn10, recQ::Tn3 mutations. The frequency of recombination between homologous DNA repeats was very high in all strains and did not decrease when the RecBCD and RecF recombinational pathways were simultaneously damaged in strains with the recB sbcBC recQ (or recF) genotype. It is assumed that unequal crossing over between direct DNA repeats in duplications may proceed through a particular pathway of "adaptive" recombination.
Sukhodolets
V V
VV
State Research Institute of Genetics and Selection of Industrial Microorganisms, Moscow, 113545 Russia. sukhodol@genetika.ru
Botina
S G
SG
Trenina
M A
MA
Ukhabotina
L S
LS
D000483:Alleles; D002869:Chromosome Aberrations; D002876:Chromosomes, Bacterial; D004269:DNA, Bacterial / Q000235:genetics; D016521:Electrophoresis, Gel, Pulsed-Field; D004926:Escherichia coli / Q000235:genetics*; D020440:Gene Duplication; D006579:Heterozygote; D009154:Mutation; D009876:Operon; D011995:Recombination, Genetic; D012091:Repetitive Sequences, Nucleic Acid
D004269:DNA, Bacterial