genotype

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genotype

(jēn`ətīp'): see geneticsgenetics,
scientific study of the mechanism of heredity. While Gregor Mendel first presented his findings on the statistical laws governing the transmission of certain traits from generation to generation in 1856, it was not until the discovery and detailed study of the
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.
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genotype (and phenotype)

the unique collection of genes an individual receives from both parents as a result of cell division (meiosis) and fusion of the ovum and sperm (fertilization). All these genes have the potential to determine, or help determine, characteristics of the individual, but not all will in fact exert an influence since they are received from both parents and the gene for a characteristic, e.g. eye colour, from one parent may be dominant over that from the other parent. The genotype therefore expresses genetic potential, and even though genes may not be expressed in the individual they will be passed on to the offspring.

While the genotype is the total genetic potential of the individual, the phenotype is the actual expression of the genes as the individual. The phenotype therefore describes the pattern of genes that have influenced the development of the individual, e.g. the gene for the individual's eye colour, but not for the eye colour not exhibited, though still carried in the genotype.

Collins Dictionary of Sociology, 3rd ed. © HarperCollins Publishers 2000
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Genotype

 

the sum total of all the genes localized in the chromosomes of a given organism. In a broader sense, the genotype is the sum total of all the hereditary factors of the organism, both nuclear (genome) and nonnuclear, or extrachromosomal (that is, cytoplasmic and plastid hereditary factors). The term was introduced by the Danish biologist W. Johannsen in 1909.

The genotype is the carrier of hereditary information, transmitted from generation to generation. It is the system that controls the development, structure, and vital activity of the organism, that is, the sum total of all the characteristics of the organism—its phenotype. The genotype is an integral system of interacting genes, so that the expression of each gene depends on the genotypic environment in which it is located. For example, the red coloration of the blossoms in some varieties of the sweet pea arises only during the simultaneous presence in the genotype of dominant alleles of two different genes, whereas separately each of these alleles causes a white coloration of the blossoms. The interaction of the genotype with the complex of factors of the internal and external environment of the organism cause a phenotypic manifestation of characteristics. The coloration of the fur of rabbits of the so-called Himalayan line serves as an example of the influence of the environment on phenotypic manifestation of genotype. Although they have one and the same genotype, these rabbits when raised in cold temperatures have black fur; when raised in moderate temperatures they have the Himalayan coloration (white with black noses, ears, feet, and tail). When raised in hot temperatures they have white fur. The offspring of these three groups of animals inherit not one immutable coloration of fur but, rather, the ability to produce a particular coloring depending on environmental conditions. Thus, in a general sense, it is more correct to say that the genotype determines the inheritance not of concrete traits but of the norm of reaction of the organism to all possible conditions of the environment. Some genes are in an active state at certain times in an individual’s development, while other genes may become active at other times; therefore, in ontogenesis the genotype functions as a changeable mobile system.

The term “genotype” is sometimes used in a much narrower sense to denote simply groups of genes or even individual genes whose inheritance is being studied. For example, the splitting offspring of the monohybrid cross AA x aa are commonly said to have genotypes AA, Aa, and aa, and the possible differences based on other genes between corresponding individuals (or groups of individuals) is disregarded.

V. I. IVANOV

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.

genotype

[′jē·nə‚tīp]
(genetics)
The genetic constitution of an organism, usually in respect to one gene or a few genes relevant in a particular context.
(systematics)
The type species of a genus.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
References in periodicals archive ?
During the first week of October, 5 guarded plants per replication for each of the genotypes were tagged for measuring seed cotton yield.
Whereas, Yp and Ys, represent yield under non-stress and yield under stress for each genotype while Ys and Yp denote average yield in stress and non-stress for all genotypes, respectively.
HCV genotype analysis was carried in SRL Lab, Mumbai using the amplicons resulting from the nested PCR using type-specific primers for the core region of the HCV genome to diagnose the genotypes 1(1a/1b),2,3 and 4.
The sampled patients were evaluated for liver echotexture through ultrasonography and genotype analysis by polymerase chain reaction.
The natural history of HCV genotypes 1, 2 and 3 seems to be similar, with patients having a high risk of developing liver cirrhosis and hepatocellular carcinoma.
Selection of superior-performance genotypes was conducted based on the MHPRVG method and on three criteria: genetic values predicted through the average behavior in all locations subjected to non-interaction conditions, genetic value predicted through genotype behavior in each location subjected to the effect of interaction; and simultaneous selection based on production, stability (MHVG) and adaptability (PRVG).
Overview and geographical distribution of HBV genotypes and subtypes
Allele type and related lipid contents of each carrier family showed significant (p = 0.04) increased levels of triglyceride in CC genotype compared to CG and GG genotypes.
A medical doctor, Mrs Senami Alawode, on Thursday advised residents of Badagry to know their genotype before wedding in order to prevent future disasters among couples.
Given the difficulty of recommending genotypes for a region, studies on agronomic performance in various cultivation environments are needed in order to detect the presence of genotypes x environments interaction.
Rapid and specific genotyping system for hepatitis B virus corresponding to six major genotypes by PCR using type-specific primers.
Leaf-level gas exchange varies among loblolly pine genotypes, and it has been implicated as a potential measure of genotype success [13-15].