Genetic recombination

Genetic recombination

Genetic recombination is the process by which a strand of genetic material (usually DNA; but can also be RNA) is broken and then joined to a different DNA molecule. In eukaryotes recombination commonly occurs during meiosis as chromosomal crossover between paired chromosomes. This process leads to offspring having different combinations of genes from their parents and can produce new chimeric alleles. In evolutionary biology this shuffling of genes is thought to have many advantages, including that of allowing sexually reproducing organisms to avoid Muller's ratchet.

In molecular biology "recombination" can also refer to artificial and deliberate recombination of disparate pieces of DNA, often from different organisms, creating what is called recombinant DNA.

Enzymes called "recombinases" catalyze natural recombination reactions. RecA, the recombinase found in E. coli, is responsible for the repair of DNA double strand breaks (DSBs). In yeast and other eukaryotic organisms there are two recombinases required for repairing DSBs. The RAD51 protein is required for mitotic and meiotic recombination and the DMC1 protein is specific to meiotic recombination.

Chromosomal crossover

Chromosomal crossover refers to recombination between the paired chromosomes inherited from each of one's parents, generally occurring during meiosis. During prophase I the four available chromatids are in tight formation with one another. While in this formation, homologous sites on two chromatids can mesh with one another, and may exchange genetic information.

Because recombination can occur with small probability at any location along chromosome, the frequency of recombination between two locations depends on their distance. Therefore, for genes sufficiently distant on the same chromosome the amount of crossover is high enough to destroy the correlation between alleles.

Gene Conversion

In gene conversion, a section of genetic material is copied from one chromosome to another, but leaves the donating chromosome unchanged.

Nonhomologous recombination

Recombination can occur between DNA sequences that contain no sequence homology. This is referred to as "Nonhomologous recombination" or nonhomologous end joining.

ee also

*Recombination frequency
*Recombination hotspot
*Four Gamete Test

External links

* [http://www.mun.ca/biochem/courses/3107/Lectures/Topics/Recombination_holliday.html The Holliday Model of Genetic Recombination]
*MeshName|Genetic+recombination
* [http://www.blackwellpublishing.com/trun/artwork/Animations/Recombination/recombination.html Animated guide to homologous recombination.]

References

*Alberts, B. et al., "Molecular Biology of the Cell", 3rd Edition. Garland Publishing, 1994.


Wikimedia Foundation. 2010.

Игры ⚽ Поможем решить контрольную работу

Look at other dictionaries:

  • genetic recombination — genetinė rekombinacija statusas T sritis augalininkystė apibrėžtis Vyksmas, kurio metu susidaro nauji genų ar chromosomų deriniai. atitikmenys: angl. genetic recombination rus. генетическая рекомбинация …   Žemės ūkio augalų selekcijos ir sėklininkystės terminų žodynas

  • genetic recombination — Formation of new combinations of alleles in offspring (viruses, cells or organisms) as a result of exchange of DNA sequences between molecules. It occurs naturally, as in crossing over between homologous chromosomes in meiosis or experimentally,… …   Dictionary of molecular biology

  • Genetic variability — is a measure of the tendency of individual genotypes in a population to vary from one another. Variability is different from genetic diversity, which is the amount of variation seen in a particular population. cite book| title=Variation and… …   Wikipedia

  • Recombination — may refer to: * Genetic recombination, the process by which genetic material is broken and joined to other genetic material * Carrier generation and recombination, processes by which mobile electrons and electron holes are created and eliminated… …   Wikipedia

  • Genetic genealogy — Part of a series on Genetic genealogy Concepts Population genetics Haplogroup/ Haplotype Most recent common ancestor Human mitochondrial DNA haplogroups Human Y chromosome DNA haplogroups Genomics Other Y chromosome haplogroups by po …   Wikipedia

  • Genetic linkage — is the tendency of certain loci or alleles to be inherited together. Genetic loci that are physically close to one another on the same chromosome tend to stay together during meiosis, and are thus genetically linked. Contents 1 Background 2… …   Wikipedia

  • genetic engineering — genetic engineer. Genetics. 1. the development and application of scientific methods, procedures, and technologies that permit direct manipulation of genetic material in order to alter the hereditary traits of a cell, organism, or population. 2.… …   Universalium

  • Genetic association — is the occurrence, more often than can be readily explained by chance, of two or more traits in a population of individuals, of which at least one trait is known to be genetic. Studies of genetic association aim to test whether single locus… …   Wikipedia

  • Genetic hitchhiking — is the process by which an evolutionarily neutral or in some cases deleterious allele or mutation may spread through the gene pool by virtue of being linked to a beneficial mutation. More generally, genetic hitchhiking can refer to the process by …   Wikipedia

  • Genetic insertion — is the addition of one or more nucleotide base pairs into a genetic sequence. This can often happen in microsatellite regions due to the DNA polymerase slipping.On a chromosome level, an insertion refers to the insertion of a larger sequence into …   Wikipedia

Share the article and excerpts

Direct link
… Do a right-click on the link above
and select “Copy Link”