Recombination

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Recombination

• Genetic perspective
• Molecular perspective
• Enzymatic perspective

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Genetic Perspective

• Involves cutting and covalent joining of DNA
  molecules
• Site-specific recombination
• Homologous recombination

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Intermolecular recombination
Genetic Perspective
A single, reciprocal cross-over or non-reciprocal
cross-over
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A double, reciprocal cross-over or non-reciprocal
cross-over
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A single, reciprocal cross-over
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Two reciprocal cross-overs or two nonreciprocal
cross-overs.
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Intramolecular recombination
Genetic Perspective
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Recombination frequency
Recombination frequencies directly proportional
to distance between two markers.
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Co-inheritance Frequency
Co-inheritance frequency is inversely
proportional to the distance between two DNA
markers.
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Single-strand invasion model
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Enzymatic Perspective

• Proteins that are involved in recombination
• RecA
• RecBCD
• RevABC
• Rus A
• RecG

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(Kei or Key)
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Chi Site

• A DNA sequence 5-GCTGGTGG-3 that promotes the
  recombination (hot spots)
• One Chi site per 5 kb in genomic DNA

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RevA and Rev B Move the Holliday Junction Along
DNA
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RuvA and RuvB move the Holliday Junction along DNA
RuvC or Rus A cleaves the junction to separate
the DNA RecG has a similar function as the
RevABC complex
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Recombination and DNA Repair

• Recombination-mediated DNA repair
• Mis-match repair in a heteroduplex region will
  mis-represent recombination frequency

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