Occurrence in an interbreeding population of two or more discontinuous genotypes
For other concepts, see Polymorphism.
Genes which control hair colour are polymorphic.
A gene is said to be polymorphic if more than one allele occupies that gene's locus within a population.[1] In addition to having more than one allele at a specific locus, each allele must also occur in the population at a rate of at least 1% to generally be considered polymorphic.[2]
Gene polymorphisms can occur in any region of the genome. The majority of polymorphisms are silent, meaning they do not alter the function or expression of a gene.[3] Some polymorphisms are visible. For example, in dogs the E locus can have any of five different alleles, known as E, Em, Eg, Eh, and e.[4] Varying combinations of these alleles contribute to the pigmentation and patterns seen in dog coats.[5]
A polymorphic variant of a gene can lead to the abnormal expression or to the production of an abnormal form of the protein; this abnormality may cause or be associated with disease. For example, a polymorphic variant of the gene encoding the enzyme CYP4A11, in which thymidine replaces cytosine at the gene's nucleotide 8590 position encodes a CYP4A11 protein that substitutes phenylalanine with serine at the protein's amino acid position 434.[6] This variant protein has reduced enzyme activity in metabolizing arachidonic acid to the blood pressure-regulating eicosanoid, 20-hydroxyeicosatetraenoic acid. A study has shown that humans bearing this variant in one or both of their CYP4A11 genes have an increased incidence of hypertension, ischemic stroke, and coronary artery disease.[6]
Most notably, the genes coding for the major histocompatibility complex (MHC) are in fact the most polymorphic genes known. MHC molecules are involved in the immune system and interact with T-cells. There are more than 32,000 different alleles of human MHC class I and II genes, and it has been estimated that there are 200 variants at the HLA-B HLA-DRB1 loci alone.[7]
Some polymorphism may be maintained by balancing selection.
^"Genetic polymorphism - Biology-Online Dictionary | Biology-Online Dictionary". September 2020.
^"Genetic Testing Report-Glossary". National Human Genome Research Institute (NHGRI). Retrieved 2017-11-08.
^Chanock, Stephen (2017-05-22). "Technologic Issues in GWAS and Follow-up Studies" (PDF). Genome.gov. Archived from the original (PDF) on 2018-08-22. Retrieved 2017-11-30.
^"Dog Coat Colour Genetics".
^"E-Locus (Recessive Yellow, Melanistic Mask Allele)". www.animalgenetics.us. Archived from the original on 2017-10-30. Retrieved 2017-11-08.
^ abWu CC, Gupta T, Garcia V, Ding Y, Schwartzman ML (2014). "20-HETE and blood pressure regulation: clinical implications". Cardiology in Review. 22 (1): 1–12. doi:10.1097/CRD.0b013e3182961659. PMC 4292790. PMID 23584425.
^Bodmer, J. G.; Marsh, S. G. E.; Albert, E. D.; Bodmer, W. F.; Bontrop, R. E.; Dupont, B.; Erlich, H. A.; Hansen, J. A.; Mach, B. (1999-04-01). "Nomenclature for factors of the HLA system, 1998". European Journal of Immunogenetics. 26 (2–3): 81–116. doi:10.1046/j.1365-2370.1999.00159.x. ISSN 1365-2370. PMID 10331156.
strand conformation polymorphism analysis. A polymorphism can be any sequence difference. Examples include: Single nucleotide polymorphisms (SNPs) are a single...
Look up polymorphism, polymorph, polymorphic, polymorphous, or polymorphy in Wiktionary, the free dictionary. Polymorphism, polymorphic, polymorph, polymorphous...
GABRR3rs832032 polymorphism and the risk for RLS, and a modifier effect of GABRA4 rs2229940 on the age of onset of RLS" - the latter of which is a modifier gene polymorphism...
or species or to pinpoint the locations of genes within a sequence. The term may refer to a polymorphism itself, as detected through the differing locations...
any parent-child combination of eye colors can occur. However, OCA2 genepolymorphism, close to proximal 5' regulatory region, explains most human eye-color...
sodium:neurotransmitter symporter family. A repeat length polymorphism in the promoter of this gene has been shown to affect the rate of serotonin uptake...
very small. The meta-analysis of 11 studies did find that another polymorphism in the gene, the -521C/T, showed an association with novelty seeking. While...
human breast cancer susceptibility gene 2 (BRCA2) is employed in DNA repair. A common single nucleotide polymorphism in BRCA2 is associated with idiopathic...
S2CID 32990396. Thurow HS, Haack R, Hartwig FP, et al. (December 2011). "TP53 genepolymorphism: importance to cancer, ethnicity and birth weight in a Brazilian cohort"...
The polymorphism survives in almost all habitats, though the proportions of morphs varies considerably. The alleles controlling the polymorphism form...
interstitial scarring which are associated with a poor prognosis. ACE genepolymorphism has been recently shown to have an impact with the DD genotype associated...
controversy over the interpretation of patterns of molecular divergence and genepolymorphism, peaking in the 1970s and 1980s. Neutral theory is frequently used...
polymorphism is the occurrence of two or more clearly different forms or phenotypes in a population of a species. Different types of polymorphism have...
Thomas S.; Musser, James M. (1997-09-02). "Restricted structural genepolymorphism in the Mycobacterium tuberculosis complex indicates evolutionarily...
Possible genepolymorphism: STAT4, PTPN2, PSORS1C1 and TRAF3IP2 genes had been correlated with response to TNF inhibitors. The HLA-DRB1 gene is part of...
known for their mane, not all males have one. This might be because of a polymorphism within males. The Asiatic lion is often considered to have a weak mane...
flexibility, and altered perceptual experiences. The rs1006737 polymorphism of the CACNA1C gene is also believed to have a part in schizotypal symptoms. It...
functional heterogeneity of eosinophil cationic protein is determined by a genepolymorphism and post-translational modifications". Clinical and Experimental Allergy...
disease and between MTHFR polymorphism status and risk for venous thromboembolism. There is growing evidence that MTHFR polymorphism testing has minimal clinical...
that there was no impact of the polymorphism on energy expenditure. This finding of an effect of the rs9939609 polymorphism on food intake or satiety has...
AP, et al. (August 2014). "Association of collagen type I alpha 1 genepolymorphism with inguinal hernia". Hernia. 18 (4): 507–12. doi:10.1007/s10029-013-1147-y...
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