Everything about Genetic Recombination totally explained
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.
Further Information
Get more info on 'Genetic Recombination'.
|
External Link Exchanges
Do you know how hard it is to get a link from a large encyclopaedia? Well we're different and will prove it. To get a link from us just add the following HTML to your site on a relevant page:
<a href="http://genetic_recombination.totallyexplained.com">Genetic recombination Totally Explained</a>
Then simply click through this link from your web page. Our crawlers will verify your link, extract the title of your web page and instantly add a link back to it. If you like you can remove the words Totally Explained and embed the link in article text.
As long as your link remains in place, we'll keep our link to you right here. Please play fair - our crawlers are watching. Your site must be closely related to this one's topic. Any kind of spamming, dubious practises or removing the link will result in your link from us being dropped and, potentially, your whole site being banned. |
