genetic variation

WordNet

1. (astronomy) any perturbation of the mean motion or orbit of a planet or satellite (especially a perturbation of the earths moon)
2. the process of varying or being varied
3. an activity that varies from a norm or standard; "any variation in his routine was immediately reported" (同)variance
4. an artifact that deviates from a norm or standard; "he patented a variation on the sandal"
5. the act of changing or altering something slightly but noticeably from the norm or standard; "who is responsible for these variations in taxation?"
6. an instance of change; the rate or magnitude of change (同)fluctuation
7. a repetition of a musical theme in which it is modified or embellished
8. pertaining to or referring to origin; "genetic history reconstructs the origins of a literary work"
9. of or relating to the science of genetics; "genetic research" (同)genetical
10. the branch of biology that studies heredity and variation in organisms (同)genetic science
11. agile Old World viverrine having a spotted coat and long ringed tail (同)Genetta genetta

PrepTutorEJDIC

1. {U}『変化(変動)すること』 / {C}(個々の)変化;変化の量(程度) / {C}変形,変わり種;(生物の)変種 / {C}(…の)変奏曲《+on+名》
2. 遺伝学

Wikipedia preview

出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2013/07/11 15:19:44」(JST)

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Genetic variation, variation in alleles of genes, occurs both within and among populations. Genetic variation is important because it provides the genetic material for natural selection. Genetic variation is brought about by mutation, which is a permanent change in the chemical structure of a gene. Polyploidy is an example of chromosomal mutation. Polyploidy is a condition wherein organisms have three or more sets of genetic variation (3n or more). The mutation is started off by a parent, as the parent mates the offspring now has a chance to receive that mutation trait also. Now when that mutated offspring is ready to mate they now have the chance of passing on that trait to their offspring. This process begins the first generation of mutated offspring.

Among individuals within a population

Genetic variation among individuals within a population can be identified at a variety of levels. It is possible to identify genetic variation from observations of phenotypic variation in either quantitative traits (traits that vary continuously and are coded for by many genes, e.g., leg length in dogs) or discrete traits (traits that fall into discrete categories and are coded for by one or a few genes (e.g., white, pink, red petal color in certain flowers).

Genetic variation can also be identified by examining variation at the level of enzymes using the process of protein electrophoresis. Polymorphic genes have more than one allele at each locus. Half of the genes that code for enzymes in insects and plants may be polymorphic, whereas polymorphisms are less common in vertebrates.

Ultimately, genetic variation is caused by variation in the order of bases in the nucleotides in genes. New technology now allows scientists to directly sequence DNA which has identified even more genetic variation than was previously detected by protein electrophoresis. Examination of DNA has shown genetic variation in both coding regions and in the non-coding intron region of genes.

Genetic variation will result in phenotypic variation if variation in the order of nucleotides in the DNA sequence results in a difference in the order of amino acids in proteins coded by that DNA sequence, and if the resultant differences in amino acid sequence influence the shape, and thus the function of the enzyme.

Between populations

Geographic variation in genes often occurs among populations living in different locations. Geographic variation may be due to differences in selective pressures or to genetic drift.

Measurement

Genetic variation within a population is commonly measured as the percentage of gene loci that are polymorphic or the percentage of gene loci in individuals that are heterozygous.

Sources

Mutations are the ultimate source of genetic variation. Mutations are likely to be rare and most mutations are neutral or deleterious, but in some instances the new alleles can be favored by natural selection.

Genetic variation can also be produced by the recombination of chromosomes that occurs during sexual reproduction, called independent assortment.

Crossing over and random segregation during meiosis can result in the production of new alleles or new combinations of alleles. Furthermore, random fertilization also contributes to variation.

Variation and recombination can be facilitated by transposable and transposed genetic elements, commonly known as endogenous retroviruses, LINEs, SINEs, etc.

Maintenance in populations

A variety of factors maintain genetic variation in populations. Potentially harmful recessive alleles can be hidden from selection in the heterozygous individuals in populations of diploid organisms (recessive alleles are only expressed in the less common homozygous individuals). Natural selection can also maintain genetic variation in balanced polymorphisms. Balanced polymorphisms may occur when heterozygotes are favored or when selection is frequency dependent.

See also

• Genetic diversity
• Human genetic variation
• Meiosis

References

Further reading

• McGinley, Mark (Lead Author); J. Emmett Duffy (Topic Editor). 2008. "Genetic variation." In: Encyclopedia of Earth. Eds. Cutler J. Cleveland (Washington, D.C.: Environmental Information Coalition, National Council for Science and the Environment). [First published in the Encyclopedia of Earth February 6, 2007; Last revised January 4, 2008; Retrieved July 8, 2009]. <http://www.eoearth.org/article/Genetic_variation>
• "Genetic Variation" in Griffiths, A.J.F. Modern Genetic Analysis, Vol 2., p. 7
• "How is Genetic Variation Maintained in Populations" in Sadava, D. et al. Life: The Science of Biology, p. 456

External links

• Genetic variation

UpToDate Contents

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• 1. 遺伝的変異の概要 overview of genetic variation
• 2. 遺伝性疾患の基本原則 basic principles of genetic disease
• 3. 輸血によるHIV感染およびAIDS transfusion transmitted hiv infection and aids
• 4. 複合形質の遺伝の原則 principles of complex trait genetics
• 5. オーダーメイド医療 personalized medicine

English Journal

• Aibika (Abelmoschus manihot L.): Genetic variation, morphology and relationships to micronutrient composition.

• Rubiang-Yalambing L1, Arcot J2, Greenfield H1, Holford P3.
• Food chemistry.Food Chem.2016 Feb 15;193:62-8. doi: 10.1016/j.foodchem.2014.08.058. Epub 2014 Aug 23.
• Aibika (Abelmoschus manihot L.) is believed to be a good source of micronutrients. However, although many varieties of aibika are commonly consumed in Papua New Guinea, their micronutrient content is unknown. Therefore, the mineral (Ca, Fe, K, Mg, Mn, Na, Zn & Cu), folate composition and the gen
• PMID 26433288

• Glutamatergic and GABAergic susceptibility loci for heroin and cocaine addiction in subjects of African and European ancestry.

• Levran O1, Peles E2, Randesi M3, Correa da Rosa J4, Ott J5, Rotrosen J6, Adelson M7, Kreek MJ3.
• Progress in neuro-psychopharmacology & biological psychiatry.Prog Neuropsychopharmacol Biol Psychiatry.2016 Jan 4;64:118-23. doi: 10.1016/j.pnpbp.2015.08.003. Epub 2015 Aug 12.
• BACKGROUND: Drug addiction, a leading health problem, is a chronic brain disease with a significant genetic component. Animal models and clinical studies established the involvement of glutamate and GABA neurotransmission in drug addiction. This study was designed to assess if 258 variants in 27 gen
• PMID 26277529

Japanese Journal

• 静岡県の在来アマゴに見られた地域変異

• 川嶋 尚正
• 日本生物地理学会会報 69, 11-21, 2014-12-20
• NAID 40020316704

• Horticultural characterization of a tetraploid transgenic plant of Tricyrtis sp. carrying the gibberellin 2-oxidase gene

• Otani Masahiro,Ishibe Mitsuyo,Inthima Phithak [他]
• Plant Biotechnology 31(4), 335-340, 2014-12
• NAID 40020313518

Related Links

• Genetic Variation - Biology

In genetic variation, the alleles of organisms within a population change. ... The genes for retinoblastoma can be acquired by genetic variation through a spontaneous gene mutation (yellow) in a child as a newborn to 18 months of age.

• Genetic Variation - National Human Genome Research ...

Understanding human genetic variation Most variation is “meaningless” – it does not affect our ability to survive or adapt Example: “silent mutations” in DNA, which change the DNA, but does not change the amino acid the DNA ...

Related Pictures

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★リンクテーブル★

リンク元	「genetic diversity」「遺伝的変異」
関連記事	「variation」「genetic」「genet」

「genetic diversity」

　　[★]

• 遺伝的多様性

関

genetic heterogeneity、genetic variation

「遺伝的変異」

　　[★]

英

heritable mutation, genetic variation

関

遺伝的多様性

「variation」

　　[★]

• 変動、バリエーション、差異、変化、変異、異形、変分

関

alter、alteration、change、difference、disparity、distinction、fluctuate、fluctuation、heteromorphic、heteromorphy、mutant、mutate、mutation、oscillate、shift、transmutation、turn、turn to、variance、variant、variational、vary

　 　 　 　 　 　 　 　

「genetic」

　　[★]

• adj.

• 遺伝的な、遺伝学的な、遺伝子の、ジェネティックな

関

gene、genetically、heritable、heritably

　 　

「genet」

　　[★]

• n.

• ジェネット、栄養繁殖集合体

関

Viverridae