Dictionary:
phe·no·type (fē'nə-tīp')  |
| 5min Related Video: phenotype |
| World of the Body: phenotype |
Pheno derives from the Greek for display: the phenotype is the manifestation of the genetic make-up of the individual.
‘Old Blue Eyes’ was the name given by many to Frank Sinatra. Having blue eyes is a trait that was part of his phenotype and is genetically determined, dependent on the genetic material derived from both parents. Of course a person's parents do not necessarily both have the same coloured eyes, and an individual may receive eye colour genes specifying different colours from their mother and father. In this situation one gene has dominance over the other gene, which is said to be recessive. Recessive genes can of course be passed on to progeny, and may be expressed in the next generation if dominance is not present.
Eye colour and hair colour are simple traits, but much more complex traits, such as general body form and appearance, result from the complex interplay of many genes derived from both parents. Many children grown up to look very like their mother or father, while most resemble neither very closely because of the considerable mix of the genetic material. Nuture is also able to modify the phenotype — for example, someone with the genetic make-up to express an obese phenotype would not do so if malnourished.
Some diseases that have a genetic basis give rise to unusual phenotypes. For example, children born with cystic fibrosis have inherited an abnormal gene from both parents that results in inappropriate secretions in many hollow organs, such as the lungs, intestine, gall bladder, or pancreas. This abnormal phenotype is usually not expressed by either of the parents, each of whom has one normal gene which is dominant and one abnormal gene which is recessive. The child receiving a set of two abnormal genes, one from each parent, will express these and show the abnormal phenotype.
— Alan W. Cuthbert
See also genetics, human; heredity.
| Dental Dictionary: phenotype |
Term referring to the expression of genotypes that can be directly distinguished (e.g., by clinical observation of external appearance or serologic tests).
| Britannica Concise Encyclopedia: phenotype |
For more information on phenotype, visit Britannica.com.
| Philosophy Dictionary: phenotype |
The gross physical and physiological features of an organism produced by the interaction of its genes and the environment. Contrasted with the genotype, which is an organism's genetic constitution: this may include recessive genes, or those that are not expressed and have no effect on the phenotype. See also heritability.
| Sports Science and Medicine: phenotype |
The observable characteristics of an individual, determined by both the genotype and environment.
| Science Dictionary: phenotype |
The outward appearance of an organism; the expression of a genotype in the form of traits that can be seen and measured, such as hair or eye color.
| Veterinary Dictionary: phenotype |
1. the outward appearance of the animal in all of its anatomical, physiological and behavioral characteristics as dictated by the genetic and environmental influences in its environment; in contradistinction to genotype in which only the inherited factors are taken into account.
2. an individual exhibiting a certain phenotype; a trait expressed in a phenotype.
| Wikipedia: Phenotype |
A phenotype is any observable characteristic or trait of an organism: such as its morphology, development, biochemical or physiological properties, or behavior. Phenotypes result from the expression of an organism's genes as well as the influence of environmental factors and possible interactions between the two. The genotype of an organism is the inherited instructions it carries within its genetic code. Not all organisms with the same genotype look or act the same way because appearance and behavior are modified by environmental and developmental conditions. Similarly, not all organisms that look alike necessarily have the same genotype. This genotype-phenotype distinction was proposed by Wilhelm Johannsen in 1911 to make clear the difference between an organism's heredity and what that heredity produces.[1][2] The distinction is similar to that proposed by August Weismann, who distinguished between germ plasm (heredity) and somatic cells (the body). A more modern version is Francis Crick's Central dogma of molecular biology.
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Despite its seemingly straightforward definition, the concept of the phenotype has some hidden subtleties. First, most of the molecules and structures coded by the genetic material are not visible in the appearance of an organism, yet they are observable (for example by Western blotting) and are thus part of the phenotype. Human blood groups are an example. So, by extension, the term phenotype must include characteristics that can be made visible by some technical procedure. Another extension adds behaviour to the phenotype since behaviours are also affected by both genotypic and environmental factors.
Phenotypic variation (due to underlying heritable genetic variation) is a fundamental prerequisite for evolution by natural selection. It is the living organism as a whole that contributes (or not) to the next generation, so natural selection affects the genetic structure of a population indirectly via the contribution of phenotypes. Without phenotypic variation, there would be no evolution by natural selection.
The interaction between genotype and phenotype has often been conceptualized by the following relationship:
A slightly more nuanced version of the relationships is:
Genotypes often have much flexibility in the modification and expression of phenotypes, in many organisms these phenotypes are very different under varying environmental conditions. The plant Hieracium umbellatum is found growing in two different habitats in Sweden. One habitat is rocky, sea-side cliffs, where the plants are bushy with broad leaves and expanded inflorescences; the other is among sand dunes where the plants grow prostrate with narrow leaves and compact inflorescences. These habitats alternate along the coast of Sweden and the habitat that the seeds of Hieracium umbellatum land in, determine the phenotype that grows.[3]
An example of random variation in Drosophila flies is the number of ommatidia, which may vary (randomly) between left and right eyes in a single individual as much as they do between different genotypes overall, or between clones raised in different environments.
The concept of phenotype can be extended to variations below the level of the gene that affect an organism's fitness. For example, silent mutations that do not change the corresponding amino acid sequence of a gene may change the frequency of guanine-cytosine base pairs (GC content). These base pairs have a higher thermal stability (melting point, see also DNA-DNA hybridization) than adenine-thymine, a property that might convey, among organisms living in high-temperature environments, a selective advantage on variants enriched in GC content.
The idea of the phenotype has been generalized by Richard Dawkins in The Extended Phenotype to mean all the effects a gene has on the outside world that may influence its chances of being replicated. These can be effects on the organism in which the gene resides, the environment, or other organisms. For instance, a beaver dam might be considered a phenotype of beaver genes, the same way beavers' powerful incisor teeth are phenotype expressions of their genes. Dawkins also cites the effect of an organism on the behaviour of another organism, such as the devoted nurturing of a cuckoo by a parent clearly of a different species as an example of the extended phenotype.
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| Translations: Phenotype |
Dansk (Danish)
n. - fremtoningspræg
Français (French)
n. - phénotype
Deutsch (German)
n. - Phenotypus
Ελληνική (Greek)
n. - φαινότυπος
Português (Portuguese)
n. - fenótipo (m) (Biol.)
Español (Spanish)
n. - fenotipo
Svenska (Swedish)
n. - fenotyp
中文（简体）(Chinese (Simplified))
显型
中文（繁體）(Chinese (Traditional))
n. - 顯型
한국어 (Korean)
n. - 표현형(생물의 표면적인 형질)
العربيه (Arabic)
(الاسم) نشأة أنموطيه
עברית (Hebrew)
n. - מכלול מאפיינים נצפים של יחיד או קבוצה (ביולוגיה)
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 | human genetics |
| heredity |
| clonotype |
 | What is a phenotypic ratio? Read answer... |
| An organisms phenotype is its? Read answer... |
| How is a phenotype determined? Read answer... |
 | What is a organisms phenotype? |
| What is a phenotypic distribution? |
| What is an extended phenotype? |
Copyrights:
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 | Dictionary. The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved. Read more |
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| World of the Body. The Oxford Companion to the Body. Copyright © 2001, 2003 by Oxford University Press. All rights reserved. Read more |
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| Dental Dictionary. Mosby's Dental Dictionary. Copyright © 2004 by Elsevier, Inc. All rights reserved. Read more |
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| Britannica Concise Encyclopedia. Britannica Concise Encyclopedia. © 2006 Encyclopædia Britannica, Inc. All rights reserved. Read more |
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| Philosophy Dictionary. The Oxford Dictionary of Philosophy. Copyright © 1994, 1996, 2005 by Oxford University Press. All rights reserved. Read more |
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| Sports Science and Medicine. The Oxford Dictionary of Sports Science & Medicine. Copyright © Michael Kent 1998, 2006, 2007. All rights reserved. Read more |
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| Science Dictionary. The New Dictionary of Cultural Literacy, Third Edition Edited by E.D. Hirsch, Jr., Joseph F. Kett, and James Trefil. Copyright © 2002 by Houghton Mifflin Company. Published by Houghton Mifflin. All rights reserved. Read more |
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| Veterinary Dictionary. Saunders Comprehensive Veterinary Dictionary 3rd Edition. Copyright © 2007 by D.C. Blood, V.P. Studdert and C.C. Gay, Elsevier. All rights reserved. Read more |
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| Wikipedia. This article is licensed under the Creative Commons Attribution/Share-Alike License. It uses material from the Wikipedia article "Phenotype". Read more |
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