Short answer
A gene is a stretch of DNA with a functional product. An allele is a particular version of DNA at a genomic location—often one version of a gene. The same gene can have many alleles in a population, while a person typically carries two alleles at an autosomal locus, one inherited from each parent. 1 2 3
An allele is a version at a genetic locus; gene names the functional sequence or locus whose versions may differ.
On this page
At a glance
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| Question | Gene | Allele |
|---|---|---|
| Main question | What functional sequence is this? | Which version is present here? |
| Scale | Locus or functional unit | Sequence alternative at that locus |
| Example | A gene associated with a blood-group trait | One inherited sequence version of that gene |
The table summarizes the cited definitions and the article’s stated scope. 1 2 3
What each thing is
Gene. A DNA sequence that produces a functional RNA product, sometimes used to make a protein. 1
Allele. One version of a DNA sequence at a particular genomic location, often described as a version of a gene. 2
Key differences
A gene and its alleles are not separate stacked objects: an allele is a way that DNA at the gene location can differ. In a diploid person, the two copies at an autosomal locus may be the same or different alleles. The population may contain more alternatives than any one person carries. 1 2 3
Think of a gene name as identifying a functional region, while an allele label tells you which sequence occurs at that region on a particular chromosome. This is why a genetics report can state a gene name once but list two inherited allele calls for a person. An allele is not a smaller physical compartment inside the gene; it is a sequence alternative. 1 2 3
How to tell them apart
If a sentence names a functional DNA unit regardless of its version, use gene. If it identifies which alternative sequence or inherited form appears at that location, use allele. Ask whether changing the sequence would still leave you discussing the same genomic locus. 1 2 3
Where they overlap
Both terms concern DNA at a location in the genome and both are used to explain inheritance. A gene can be discussed through the alleles observed at its locus. 1 2 3
Edge cases
Genetics also calls alternative sequences at non-gene locations alleles. Some genes produce functional RNA without coding for a protein, so “gene equals protein recipe” is too narrow. Copy-number changes complicate the everyday picture of exactly two copies. 1 2 3
The shorthand of “two alleles per gene” applies most neatly to ordinary autosomal loci in diploid cells. Sex-linked regions, copy-number changes and differences among cell populations can require a more careful account. Even a sequence outside a protein-coding gene can have alternative alleles at its locus. 1 2 3
Why the distinction exists
The distinction lets geneticists separate the shared biological unit from the different inherited versions people carry. That is why a single gene name can coexist with several allele symbols. 1 2 3
Common misconceptions
“A person has one gene or another allele” mixes levels. Someone can share the same gene location with another person yet carry a different allele there. 1 2 3
Examples
At a simple autosomal locus, a person with allele A on one chromosome and allele a on its partner has two versions of the same locus, not two unrelated genes. 1 2 3
Sources
Sources checked October 3, 2026.
- National Human Genome Research Institute — Gene. Definition and narration.
- National Human Genome Research Institute — Allele. Definition and narration.
- National Human Genome Research Institute — Genotype. Definition.