(redirected from Null allele)
Also found in: Thesaurus, Medical, Encyclopedia, Wikipedia.
Related to Null allele: Null mutation


Any of the alternative forms of a gene or other homologous DNA sequence. Also called allelomorph.

[German Allel, short for Allelomorph, allelomorph, from English allelomorph.]

al·le′lic (ə-lē′lĭk, ə-lĕl′ĭk) adj.
al·le′lism n.
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.


(əˈliːl) or


(Genetics) any of two or more variants of a gene that have the same relative position on homologous chromosomes and are responsible for alternative characteristics, such as smooth or wrinkled seeds in peas. Also called: allelomorph See also multiple alleles
[C20: from German Allel, shortened from allelomorph, from Greek allēl- one another + morphē form]
alˈlelic adj
alˈlelism n
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014



one of two or more alternative forms of a gene occupying the same position on matching chromosomes: an individual normally has two alleles for each trait, one from either parent.
[1930–35; < German Allel, appar. as shortening of German equivalents of allelomorph or allelomorphic gene]
al•lel•ic (əˈli lɪk, əˈlɛl ɪk) adj.
al•lel′ism, n.
Random House Kernerman Webster's College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.


Any of the possible forms in which a gene for a specific trait can occur. In almost all animal cells, two alleles for each trait are inherited, one from each parent. Alleles on each of a pair of chromosomes are called homozygous if they are similar to each other and heterozygous if they are different.
The American Heritage® Student Science Dictionary, Second Edition. Copyright © 2014 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.allele - (genetics) either of a pair (or series) of alternative forms of a gene that can occupy the same locus on a particular chromosome and that control the same characterallele - (genetics) either of a pair (or series) of alternative forms of a gene that can occupy the same locus on a particular chromosome and that control the same character; "some alleles are dominant over others"
cistron, gene, factor - (genetics) a segment of DNA that is involved in producing a polypeptide chain; it can include regions preceding and following the coding DNA as well as introns between the exons; it is considered a unit of heredity; "genes were formerly called factors"
dominant allele, dominant - an allele that produces the same phenotype whether its paired allele is identical or different
recessive, recessive allele - an allele that produces its characteristic phenotype only when its paired allele is identical
genetic science, genetics - the branch of biology that studies heredity and variation in organisms
Based on WordNet 3.0, Farlex clipart collection. © 2003-2012 Princeton University, Farlex Inc.


n. alelo, alelomorfo, uno de dos o más genes de una serie que ocupa la misma posición en cromosomas homólogos y que determina características alternantes en los descendientes.
English-Spanish Medical Dictionary © Farlex 2012
References in periodicals archive ?
However, out of 16 total loci there was one (Pdo6) that deviated from HW equilibrium, it has estimated null allele frequency of 0.008.
Statistical Analysis: Odds ratio (OR) with 95% confidence interval (CI) was calculated to measure the risk conferred by null allele of GSTM1 and GSTT1 for the disease.
Another explanation for the high inbreeding values lies on the presence of null alleles, because it increases the number of homozygous individuals, since just one of the alleles amplifies itself in cases of null allele in heterozygous plant (Nybom, 2004).
Null allele at the OarAE129 locus and corresponding allele frequencies in German sheep breeds.
Conventionally, gene sequencing has been employed only when a rare or null allele is suspected after first tier tests [4].
It is possible that, as noted in our study group of diabetic children, decreased antioxidant enzymatic activity due to GST T1 null allele, together with one of the tentative potentials due to GST M1 wild allele, constitutes a risk factor for T1DM.
2007) software on the basis of all adult individual's genotypes (without recapture individuals, n = 77): deviation from Hardy-Weinberg equilibrium, observed and expected heterozygosity and a null allele (i.e.
(2,3) IR8 contains a 383-bp deletion from exon 1 to exon 2 in SD-1, which produces a null allele carrying a premature stop codon.n) On the other hand, some japonica varieties, such as Jikkoku, Reimei and Calrose76, which also contributed to the increased crop productivity in Japan and US, carry single-nucleotide substitutions leading to amino acid changes that only partially disrupt or weaken GA synthesis.
For those markers where departures from Mendelian expectation occurred, the family group exhibited a potential null allele or an unexpected band was observed, both parents and 6 progeny were selected and DNA amplified.
Frequency of null allele ranged from 0.01 to 0.19 for mature trees and from 0.04 to 0.17 for juveniles.
Thus, c.13C>T (p.Arg5X) is a predicted null allele in a haploinsufficient gene.