Practice question

Physical mapping of Chi activity identified consensus octamer as recombination stimulator in Escherichia coli and related enteric bacteria. Sequence 5'-GCTGGTGG-3' is statistically overrepresented in E. coli genome particularly on leading strand core orientation consistent with break repair bias. Orientation-specific hotspot elevates recombination roughly eightfold in its vicinity downstream, but only when encountered from defined direction relative to RecBCD entry due to asymmetric recognition. This sequence is absent in unrelated organisms using different Chi; Bacillus AddAB recognizes unrelated pentamer, demonstrating species-specific adaptation linking Chi recognition to RecC structural diversity.