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Neofunctionalization
Neofunctionalization, one of the possible outcomes of functional divergence, occurs when one gene copy, or paralog, takes on a totally new function after a gene duplication event. Neofunctionalization is an adaptive mutation process; meaning one of the gene copies must mutate to develop a function that was not present in the ancestral gene. In other words, one of the duplicates retains its original function, while the other accumulates molecular changes such that, in time, it can perform a different task. The process The process of Neofunctionalization begins with a gene duplication event, which is thought to occur as a defense mechanism against the accumulation of deleterious mutations. Following the gene duplication event there are two identical copies of the ancestral gene performing exactly the same function. This redundancy allows one the copies to take on a new function. In the event that the new function is advantageous, natural selection positively selects for it and th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neofunctionalization After A Gene Duplication Event
Neofunctionalization, one of the possible outcomes of functional divergence, occurs when one gene copy, or paralog, takes on a totally new function after a gene duplication event. Neofunctionalization is an adaptive mutation process; meaning one of the gene copies must mutate to develop a function that was not present in the ancestral gene. In other words, one of the duplicates retains its original function, while the other accumulates molecular changes such that, in time, it can perform a different task. The process The process of Neofunctionalization begins with a gene duplication event, which is thought to occur as a defense mechanism against the accumulation of deleterious mutations. Following the gene duplication event there are two identical copies of the ancestral gene performing exactly the same function. This redundancy allows one the copies to take on a new function. In the event that the new function is advantageous, natural selection positively selects for it and th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gene Duplication
Gene duplication (or chromosomal duplication or gene amplification) is a major mechanism through which new genetic material is generated during molecular evolution. It can be defined as any duplication of a region of DNA that contains a gene. Gene duplications can arise as products of several types of errors in DNA replication and repair machinery as well as through fortuitous capture by selfish genetic elements. Common sources of gene duplications include ectopic recombination, retrotransposition event, aneuploidy, polyploidy, and replication slippage. Mechanisms of duplication Ectopic recombination Duplications arise from an event termed unequal crossing-over that occurs during meiosis between misaligned homologous chromosomes. The chance of it happening is a function of the degree of sharing of repetitive elements between two chromosomes. The products of this recombination are a duplication at the site of the exchange and a reciprocal deletion. Ectopic recombination ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Subfunctionalization
Subfunctionalization was proposed by Stoltzfus (1999) and Force et al. (1999) as one of the possible outcomes of functional divergence that occurs after a gene duplication event, in which pairs of genes that originate from duplication, or paralogs, take on separate functions. Subfunctionalization is a neutral mutation process of constructive neutral evolution; meaning that no new adaptations are formed. During the process of gene duplication paralogs simply undergo a division of labor by retaining different parts (subfunctions) of their original ancestral function. This partitioning event occurs because of segmental gene silencing leading to the formation of paralogs that are no longer duplicates, because each gene only retains a single function. It is important to note that the ancestral gene was capable of performing both functions and the descendant duplicate genes can now only perform one of the original ancestral functions. Alternative Hypothesis Subfunctionalization after ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Subfunctionalization
Subfunctionalization was proposed by Stoltzfus (1999) and Force et al. (1999) as one of the possible outcomes of functional divergence that occurs after a gene duplication event, in which pairs of genes that originate from duplication, or paralogs, take on separate functions. Subfunctionalization is a neutral mutation process of constructive neutral evolution; meaning that no new adaptations are formed. During the process of gene duplication paralogs simply undergo a division of labor by retaining different parts (subfunctions) of their original ancestral function. This partitioning event occurs because of segmental gene silencing leading to the formation of paralogs that are no longer duplicates, because each gene only retains a single function. It is important to note that the ancestral gene was capable of performing both functions and the descendant duplicate genes can now only perform one of the original ancestral functions. Alternative Hypothesis Subfunctionalization after ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Functional Divergence
Functional divergence is the process by which genes, after gene duplication, shift in function from an ancestral function. Functional divergence can result in either subfunctionalization, where a paralog specializes one of several ancestral functions, or neofunctionalization, where a totally new functional capability evolves. It is thought that this process of gene duplication and functional divergence is a major originator of molecular novelty and has produced the many large protein families that exist today. Functional divergence is just one possible outcome of gene duplication events. Other fates include nonfunctionalization where one of the paralogs acquires deleterious mutations and becomes a pseudogene and superfunctionalization (reinforcement), where both paralogs maintain original function. While gene, chromosome, or whole genome duplication events are considered the canonical sources of functional divergence of paralogs, orthologs (genes descended from speciation events) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paralog
Sequence homology is the biological homology between DNA, RNA, or protein sequences, defined in terms of shared ancestry in the evolutionary history of life. Two segments of DNA can have shared ancestry because of three phenomena: either a speciation event (orthologs), or a duplication event (paralogs), or else a horizontal (or lateral) gene transfer event (xenologs). Homology among DNA, RNA, or proteins is typically inferred from their nucleotide or amino acid sequence similarity. Significant similarity is strong evidence that two sequences are related by evolutionary changes from a common ancestral sequence. Alignments of multiple sequences are used to indicate which regions of each sequence are homologous. Identity, similarity, and conservation The term "percent homology" is often used to mean "sequence similarity”, that is the percentage of identical residues (''percent identity''), or the percentage of residues conserved with similar physicochemical properties ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Susumu Ohno
Susumu is a masculine Japanese given name. Notable people with the name include: * Susumu Akagi (born 1972) Japanese voice actor * Susumu Aoyagi (青柳 進, born 1968), Japanese baseball player *Susumu Chiba (born 1970), Japanese voice actor *, Japanese bobsledder * Susumu Fujita (1912–1991), Japanese actor *Susumu Fukui (born 1947), Japanese Go player * Susumu Hani (born 1928), Japanese film director *, Japanese ice hockey player *Susumu Hirasawa (born 1954), Japanese progressive-electronic artist *Susumu Ishii (1924–1991), Japanese criminal *, Japanese urologist *Susumu Kajiyama (born around 1950), Japanese criminal *Susumu Katsumata (other), multiple people * Susumu Kitagawa (born 1951), Japanese chemist *, Japanese sport shooter *Susumu Kuno (born 1933), Japanese linguist and author *Susumu Kurobe (born 1939), Japanese actor * Susumu Matsushima (born 1913), Japanese photographer * Susumu Matsushita (born 1950), Japanese manga artist. *Susumu Mochizuki (born 1978), ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hermann Joseph Muller
Hermann Joseph Muller (December 21, 1890 – April 5, 1967) was an American geneticist, educator, and Nobel laureate best known for his work on the physiological and genetic effects of radiation ( mutagenesis), as well as his outspoken political beliefs. Muller frequently warned of long-term dangers of radioactive fallout from nuclear war and nuclear testing, which resulted in greater public scrutiny of these practices. Early life Muller was born in New York City, the son of Frances (Lyons) and Hermann Joseph Muller Sr., an artisan who worked with metals. Muller was a third-generation American whose father's ancestors were originally Catholic and came to the United States from Koblenz. His mother's family was of mixed Jewish (descended from Spanish and Portuguese Jews) and Anglican background, and had come from Britain. Among his first cousins are Herbert J. Muller and Alfred Kroeber (Kroeber is Ursula Le Guin's father). As an adolescent, Muller attended a Unitarian church ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tomoko Ohta
Tomoko (ともこ, トモコ) is a female Japanese given name. Like many Japanese names, Tomoko can be written using different kanji characters and can mean: * 友子 - "friendly child" * 知子 - "knowing child" * 智子 - "wise child" * 朋子 - "friendly child" * 皆子 - "beautiful girl" * 詩子 - "poetic child" People with the name * , Japanese politician * , Japanese voice actress * Tomoko Aran (荒野智子), born January 14, 1958, Japanese city pop artist * , Japanese judoka * , Japanese origami writer * , Japanese swimmer * , Japanese announcer * , Japanese actress and essayist * , Japanese motorcycle racer * , Japanese actress * , Japanese voice actress * , Japanese politician * , victim of Minamata disease and subject of the photo '' Tomoko and Mother in the Bath'' * , Japanese singer * , Japanese voice actress * , Japanese artist * , Japanese voice actress * , Japanese singer * , Japanese professional wrestler * , Japanese singer, part of 1980s J-Pop duo BaBe * , ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antarctic Zoarcid Fish
The Antarctic ( or , American English also or ; commonly ) is a polar region around Earth's South Pole, opposite the Arctic region around the North Pole. The Antarctic comprises the continent of Antarctica, the Kerguelen Plateau and other island territories located on the Antarctic Plate or south of the Antarctic Convergence. The Antarctic region includes the ice shelves, waters, and all the island territories in the Southern Ocean situated south of the Antarctic Convergence, a zone approximately wide varying in latitude seasonally. The region covers some 20 percent of the Southern Hemisphere, of which 5.5 percent (14 million km2) is the surface area of the Antarctica continent itself. All of the land and ice shelves south of 60°S latitude are administered under the Antarctic Treaty System. Biogeographically, the Antarctic realm is one of eight biogeographic realms of Earth's land surface. Geography As defined by the Antarctic Treaty System, the Antarctic r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pseudogene
Pseudogenes are nonfunctional segments of DNA that resemble functional genes. Most arise as superfluous copies of functional genes, either directly by DNA duplication or indirectly by reverse transcription of an mRNA transcript. Pseudogenes are usually identified when genome sequence analysis finds gene-like sequences that lack regulatory sequences needed for transcription or translation, or whose coding sequences are obviously defective due to frameshifts or premature stop codons. Most non-bacterial genomes contain many pseudogenes, often as many as functional genes. This is not surprising, since various biological processes are expected to accidentally create pseudogenes, and there are no specialized mechanisms to remove them from genomes. Eventually pseudogenes may be deleted from their genomes by chance DNA replication or DNA repair errors, or they may accumulate so many mutational changes that they are no longer recognizable as former genes. Analysis of these degenerati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
