allele

American  

[uh-leel] / əˈlil /

noun

Genetics.

1. any of several forms of a gene, usually arising through mutation, that are responsible for hereditary variation.

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allele British  

/ əˈliːl /

noun

1. Also called: allelomorph.  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 See also multiple alleles

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allele Scientific  

/ ə-lēl′ /

1. Any of the possible forms in which a gene for a specific trait can occur. In almost all animal cells, two alleles for each gene are inherited, one from each parent. Paired alleles (one on each of two paired chromosomes) that are the same are called homozygous, and those that are different are called heterozygous. In heterozygous pairings, one allele is usually dominant, and the other recessive. Complex traits such as height and longevity are usually caused by the interactions of numerous pairs of alleles, while simple traits such as eye color may be caused by just one pair.

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allele Cultural  

1. The sequence of nucleotides on a DNA molecule that constitutes the form of a gene at a specific spot or a chromosome. There can be several variations of this sequence, and each of these is called an allele. In the case of the gene for eye color, for example, one allele codes for blue eyes, whereas the other may code for brown eyes.

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Other Word Forms

• allelism
  noun
• allelic
  adjective
• interallelic
  adjective
• nonallelic
  adjective

Etymology

Origin of allele

First recorded in 1930–35; from German Allel, apparently as shortening of German equivalents of allelomorph or allelomorphic gene; allelo-, from Greek allēlo-, combining form of allḗlōn “of/to one another, reciprocally”

Explanation

An allele is one of a pair of genes that appear at a particular location on a particular chromosome and control the same characteristic, such as blood type or color blindness. Alleles are also called alleleomorphs. Your blood type is determined by the alleles you inherited from your parents. If your mother's blood type is A and you know she's homozygous (that is, her alleles are the same, both of them A) and your father's blood type is O (since type O is a recessive trait, he would have to be homozygous, too), then you’ve inherited an A and an O allele — and your blood type is A.

Example Sentences

See Examples For:

allele

In genomic imprinting, an allele can be chemically marked through a process called methylation and effectively switched off.

From Science Daily ● Jun. 1, 2026

In one study published in the journal Hypertension, people who had the “slow” caffeine metabolizing gene allele were at an increased risk of hypertension compared to those who had the “fast” gene allele.

From Salon ● Dec. 22, 2024

Notably, an ancestry-biased mRNA isoform of SPSB2, likely driven by cross-population allele frequency differences in rs11064437, was found to be unannotated in canonical gene annotation.

From Science Daily ● Dec. 4, 2024

"The people who have the minor allele variant of the SNP convert ethanol to acetaldehyde very rapidly. And that causes a lot of negative effects," said Sanchez-Roige.

From Science Daily ● Apr. 5, 2024

Only one allele had asserted itself in the hybrid, forcing the other variant trait to vanish.

From "The Gene" by Siddhartha Mukherjee