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. Deoxyribonucleic acid ( DNA) is a Nucleic acid that contains the genetic instructions used in the development and functioning of all known Ribonucleic acid ( RNA) is a Nucleic acid that consists of a long chain of Nucleotide units In eukaryotes recombination commonly occurs during meiosis as chromosomal crossover between paired chromosomes. Animals Plants fungi, and Protists are eukaryotes (juːˈkærɪɒt or -oʊt Organisms whose cells are organized into complex In Biology or life science meiosis (pronounced my-oh-sis is a process of reductional division in which the number of chromosomes per cell is cut in half This process leads to offspring having different combinations of genes from their parents and can produce new chimeric alleles. An allele (ˈæliːl (UK /əˈliːl/ (US (from the Greek αλληλος allelos, meaning each other) is one member of a pair or series of different forms 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 Evolutionary Genetics, Muller's ratchet (named after Hermann Joseph Muller and a mechanical device) is the name given to the process by which
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. Molecular biology is the study of Biology at a molecular level Recombinant DNA is a form of synthetic DNA that is engineered through the combination or insertion of one or more DNA strands thereby combining DNA sequences
Enzymes called recombinases catalyze natural recombination reactions. Enzymes are Biomolecules that catalyze ( ie increase the rates of Chemical reactions Almost all enzymes are Proteins Catalysis is the process in which the rate of a Chemical reaction is increased by means of a Chemical substance known as a catalyst RecA, the recombinase found in E. coli, is responsible for the repair of DNA double strand breaks (DSBs). RecA is a 38 kilodalton Escherichia coli Protein essential for the repair and maintenance of DNA. In yeast and other eukaryotic organisms there are two recombinases required for repairing DSBs. Animals Plants fungi, and Protists are eukaryotes (juːˈkærɪɒt or -oʊt Organisms whose cells are organized into complex The RAD51 protein is required for mitotic and meiotic recombination and the DMC1 protein is specific to meiotic recombination. RAD51 is a human Gene. The Protein encoded by this gene is a member of the RAD51 protein family which assist in repair of DNA double strand breaks. Mitosis is the process in which a Eukaryotic cell separates the Chromosomes in its Cell nucleus, into two identical sets in two daughter nuclei In Biology or life science meiosis (pronounced my-oh-sis is a process of reductional division in which the number of chromosomes per cell is cut in half DMC1 dosage suppressor of mck1 homolog meiosis-specific homologous recombination (yeast, also known as DMC1, is a human Gene.
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Chromosomal crossover
Chromosomal crossover refers to recombination between the paired chromosomes inherited from each of one's parents, generally occurring during meiosis. A chromosome is an organized structure of DNA and Protein that is found in cells. In Biology or life science meiosis (pronounced my-oh-sis is a process of reductional division in which the number of chromosomes per cell is cut in half During prophase I the four available chromatids are in tight formation with one another. In Biology or life science meiosis (pronounced my-oh-sis is a process of reductional division in which the number of chromosomes per cell is cut in half A chromatid is one of two identical copies of DNA making up a replicated Chromosome, which are joined at their Centromeres for the process of Cell division While in this formation, homologous sites on two chromatids can mesh with one another, and may exchange genetic information. In Evolutionary biology, homology has come to mean any similarity between characters that is due to their shared ancestry.
Because recombination can occur with small probability at any location along chromosome, the frequency of recombination between two locations depends on their distance. Genetic linkage occurs when particular genetic loci or Alleles for genes are inherited jointly Therefore, for genes sufficiently distant on the same chromosome the amount of crossover is high enough to destroy the correlation between alleles. An allele (ˈæliːl (UK /əˈliːl/ (US (from the Greek αλληλος allelos, meaning each other) is one member of a pair or series of different forms
Gene Conversion
In gene conversion, a section of genetic material is copied from one chromosome to another, but leaves the donating chromosome unchanged. Gene conversion is an event in DNA Genetic recombination, which occurs at high frequencies during meiotic division but which also occurs in somatic cells
Nonhomologous recombination
Recombination can occur between DNA sequences that contain no sequence homology. Non-homologous end joining ( NHEJ) is a pathway that repairs double-strand breaks in DNA In Evolutionary biology, homology has come to mean any similarity between characters that is due to their shared ancestry. This is referred to as Nonhomologous recombination or nonhomologous end joining. Non-homologous end joining ( NHEJ) is a pathway that repairs double-strand breaks in DNA
See also
External links
- The Holliday Model of Genetic Recombination
- MeSH Genetic+recombination
- Animated guide to homologous recombination.
References
- Alberts, B. Genetic linkage occurs when particular genetic loci or Alleles for genes are inherited jointly Recombination hotspots are small regions in the genome of sexually reproducing organisms that exhibit highly elevated rates of meiotic recombination. In Population genetics, the Four Gamete Test is a method for detecting historical recombination events. Medical Subject Headings ( MeSH) is a huge Controlled vocabulary (or metadata system for the purpose of indexing journal articles and books et al. , Molecular Biology of the Cell, 3rd Edition. Garland Publishing, 1994.
This article contains material from the Science Primer published by the NCBI, which, as a U. The National Center for Biotechnology Information ( NCBI) is part of the United States National Library of Medicine (NLM a branch of the National Institutes S. government publication, is in the public domain. The public domain is a range of abstract materials &ndash commonly referred to as Intellectual property &ndash which are not owned or controlled by anyone
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