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Related to Alleles: genotype, Multiple alleles



inherited imprints (genes) located in identical parts of homologous (paired) chromosomes; they determine the developmental direction of a particular characteristic. The term was introduced by the Danish scientist W. Johannsen in 1909 to replace the term “allelomorph,” which had been proposed by the English geneticist W. Bateson in 1902. Every gene may be found in at least two allelic states (determined by its structure), one of which—the dominant allele—usually assures maximal development of a given characteristic; the other—the recessive allele—leads to partial or complete loss of the characteristic. For example, in plants, the dominant allele produces colored flowers and the recessive allele produces colorless flowers; in humans, the gene controlling eye color is present in brown-eyed persons in the form of a dominant allele (either one or a pair), and in blue-eyed persons only in the form of recessive alleles. Genes belonging to a single allelic group are denoted by a single letter—uppercase for the dominant allele and lowercase for the recessive (for example, B and b). Only one allele of a given gene can be located in each homologous chromosome. Since there are two chromosomes of every type (homologous chromosomes) in diploid organisms, there are two alleles of every type in the somatic cells of such organisms. Only one allele, together with one of the chromosomes, appears in the formation of sex cells. During fertilization (fusion of sex cells) the parity of chromosomes, and hence also of alleles, is restored. Dominant and recessive alleles may be present in the state of homozygosity (BB or bb) or heterozygosity (Bb). If a gene is present in several (more than two) different states, it forms a series of multiple alleles.


Lobashev, M. E. Genetika, 2nd ed. Leningrad, 1967.
Müntzing, A. Genetika. Moscow, 1967. (Translated from English.)


References in periodicals archive ?
Spector at Cold Spring Harbor Laboratory (CSHL) showed that the two alleles of Oct4, a gene important in embryonic stem cells, did not come together randomly, at any time or place, but did so at the developmental point at which stem cells begin their maturation into specific cell types.
Because the chromosomes come in pairs, every dog has four alleles (gene codes) for color--one from the sire and one from the dam at both locus points.
T cells were phenotyped for HLA-class I alleles (A and B), while B cells were employed in the phenotyping of HLA-class II alleles (DR and DQ) in the microlymphocytotoxicity test, (11) using a panel of monoclonal antibodies (Biotest Company, Germany) that were able to recognize 8 A, 20 B, 10 DR, and 4 DQ HLA antigens.
31,32,33) These findings have led to the concept that 5-HTT is a "plasticity gene" (34) that both alleles offer advantages but in different environments.
Another is that a tested alleged parent has copies of most, but not all of the child's alleles because he/she is a close relative of the true parent.
Interestingly, in present study only CSN1S2 F and A alleles were detected (Figure 1), while B, C, E, D and O alleles were absent.
Conclusions: Data demonstrates that frequency and distribution of mutant T allele was more prevalent as compared to wild type A allele in the study group.
At the American Heart Association Meeting in 2015, it was announced that the protective FOXO3 allele is strongly associated with reduced coronary heart disease mortality (p=0.
Generally, the allele frequencies depicted wide ranges in populations of the lower KPK when compared to the upper KPK (Fig.
Frequencies of CYP2D6 mutant alleles in a normal Japanese population and metabolic activity of dextromethorphan O-demethylation in different CYP2D6 genotypes.
With the advent and growing implementation of routine HLA genotyping by NGS within clinical immunogenetics laboratories, the pace of discovery and annotation of novel HLA alleles continues to grow.