PowerPoint Presentation - Foundations of Biology

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John 154 4 Abide in me, and I in you. As the
branch cannot bear fruit of itself, except it
abide in the vine no more can ye, except ye
abide in me
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Recombination

• Timothy G. Standish, Ph. D.

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Types Of Recombination

• Generalized or Homologous Recombination - Occurs
  during prophase of meiosis I and involves
  exchange between homologous strands of DNA
• Site Specific Recombination - Short homologous
  sections of bacterial and phage DNA serve as a
  site for recombination and thus incorporation of
  phage DNA into bacterial chromosomes
• Copy choice - Used by RNA viruses, polymerase
  switches back and forth between templates from
  different parents
• Transposition - Not truly recombination between
  different genomes, but the movement of
  transposons within a genome

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Homologous RecombinationIn Eukaryotes
As long as genes on the same chromosome are
located a long distance apart, they will assort
independently due to crossing over during
prophase I of meiosis
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The Current Eukaryotic Recombination Model
Homologous chromosomes
Meiosis Prophase I
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The Current Eukaryotic Recombination Model
Exo- nuclease
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The Current Eukaryotic Recombination Model
Exo- nuclease
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The Current Eukaryotic Recombination Model
Exo- nuclease
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The Current Eukaryotic Recombination Model
Exo- nuclease
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The Current Eukaryotic Recombination Model
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The Current Eukaryotic Recombination Model
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The Current Eukaryotic Recombination Model
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The Current Eukaryotic Recombination Model
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The Current Eukaryotic Recombination Model
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Holliday Structure
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Holliday Structure
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Holliday Structure
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Holliday Structure
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Holliday Structure
Cut
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Holliday Structure
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Holliday Structure
Cut
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Holliday Structure
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Cutting The Holliday Structure
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Four Possible Outcomes
Heteroduplex and a short recombinant area between
cuts
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Four Possible Outcomes
Heteroduplex with no recombinant area between cuts
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Four Possible Outcomes
Recombinant chromosomes joined by heteroduplex
between cuts
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Four Possible Outcomes
Recombinant chromosomes joined by heteroduplex
between cuts
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