Homologous recombination

Homologous recombination is a type of genetic recombination, a process of physical rearrangement occurring between two strands of DNA. Homologous recombination involves the alignment of similar sequences, a crossover between the aligned DNA strands, and breaking and repair of the DNA to produce an exchange of material between the strands. The process homologous recombination naturally occurs in organisms and is also utilized as a molecular biology technique for introducing genetic changes into an organism.

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Homologous recombination in organisms

Main article: Chromosomal crossover

Main article: DNA repair

The process of homologous recombination occurs during chromosomal crossover, a process occurring during meiosis in eukaryotic organisms that results in a shuffling of genetic material. Homologous recombination is also involved in DNA repair, as organisms repair a damaged region using the material from a partner chromosome as a template.^[1] In bacteria, homologous recombination introduces DNA into a bacterium through conjugation, transduction, or natural transformation.

Artificial homologous recombination

Main article: Gene targeting

Many methods for introducing DNA sequences into organisms to create recombinant DNA and genetically modified organisms use the process of homologous recombination.^[2] Also called "gene targeting", the method is especially common in yeast and mouse genetics. The gene targeting method in the mouse model utilizes mouse embryonic stem cells to deliver artificial genetic material (mostly of therapeutic interest) which represses the target gene of the mouse by the principle of homologous recombination. The mouse thereby acts as a working model to understand the effects of a specific mammalian gene (More on knockout mice). This work yielded Mario Capecchi, Martin Evans and Oliver Smithies the 2007 Nobel Prize for Physiology or Medicine.^[3]

References

1. ^ H. Lodish, A. Berk, L.S. Zipursky, P. Matsudaira, D. Baltimore, J. Darnell (2000). Molecular Cell Biology, 4th ed., W. H. Freeman and Company. ISBN 0-7167-3136-3.  12.5. Recombination between Homologous DNA Sites: Double-Strand Breaks in DNA Initiate Recombination
2. ^ H. Lodish, A. Berk, L.S. Zipursky, P. Matsudaira, D. Baltimore, J. Darnell (2000). Molecular Cell Biology, 4th ed., W. H. Freeman and Company. ISBN 0-7167-3136-3.  8.5. Gene Replacement and Transgenic Animals: DNA Is Transferred into Eukaryotic Cells in Various Ways
3. ^ The Nobel Prize in Physiology or Medicine 2007. The Nobel Foundation. Retrieved on 2007-10-08.

See also

• Genetic recombination
• Chromosomal crossover
• DNA repair
• Gene targeting