John 15 4 4 Abide in me and

John 15: 4 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 © 2001 Timothy G. Standish

Recombination Timothy G. Standish, Ph. D. © 2001 Timothy G. Standish

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 © 2001 Timothy G. Standish

Homologous Recombination In Eukaryotes Prophase I Replication er er oth ath M F E E e e E e N n n N N n As long as genes on the same n chromosome are located a long distance apart, they will assort independently due to crossing over during prophase I of meiosis E e N N E N N Telophase I n n Telophase II n E e N N n n © 2001 Timothy G. Standish

The Current Eukaryotic Recombination Model Homologous chromosomes Meiosis Prophase I © 2001 Timothy G. Standish

The Current Eukaryotic Recombination Model Exonuclease Double strand break © 2001 Timothy G. Standish

The Current Eukaryotic Recombination Model Exonuclease © 2001 Timothy G. Standish

The Current Eukaryotic Recombination Model Exonuclease © 2001 Timothy G. Standish

The Current Eukaryotic Recombination Model Exonuclease © 2001 Timothy G. Standish

The Current Eukaryotic Recombination Model DNA Polymerase © 2001 Timothy G. Standish

The Current Eukaryotic Recombination Model DNA Polymerase © 2001 Timothy G. Standish

The Current Eukaryotic Recombination Model DNA Polymerase © 2001 Timothy G. Standish

The Current Eukaryotic Recombination Model DNA Polymerase © 2001 Timothy G. Standish

The Current Eukaryotic Recombination Model Ligase Branch migration Ligase © 2001 Timothy G. Standish

Holliday Structure © 2001 Timothy G. Standish

Holliday Structure Bend © 2001 Timothy G. Standish

Holliday Structure Bend Twist © 2001 Timothy G. Standish

Holliday Structure Cut © 2001 Timothy G. Standish

Holliday Structure Cut Heteroduplex region Recombinant Strand © 2001 Timothy G. Standish

Holliday Structure Cut © 2001 Timothy G. Standish

Holliday Structure Cut Heteroduplex region Recombinant Strand © 2001 Timothy G. Standish

Holliday Structure © 2001 Timothy G. Standish

Cutting The Holliday Structure © 2001 Timothy G. Standish

Four Possible Outcomes Cut Pink Blue Cut Heteroduplex Pink Blue Heteroduplex and a short recombinant area between cuts © 2001 Timothy G. Standish

Four Possible Outcomes Cut Blue Pink Cut Cut Blue Heteroduplex Pink Heteroduplex with no recombinant area between cuts © 2001 Timothy G. Standish

Four Possible Outcomes Cut Cut Blue Pink Blue Recombinant chromosomes joined by heteroduplex between cuts © 2001 Timothy G. Standish

Four Possible Outcomes Cut Cut Pink Blue Pink Recombinant chromosomes joined by heteroduplex between cuts © 2001 Timothy G. Standish

© 2001 Timothy G. Standish