Encyclopedia of Animal Cognition and Behavior

Living Edition
| Editors: Jennifer Vonk, Todd Shackelford


  • Damini JaiswalEmail author
Living reference work entry
DOI: https://doi.org/10.1007/978-3-319-47829-6_29-1



Alleles are variant forms of a gene that differ in sequence information.

What Are Alleles at Genetic Level?

The term allele refers to variant forms of a gene. A gene can be considered as any stretch of the DNA that gets transcribed, i.e., gets converted to RNA. So, a gene is basically a sequence of nucleotides that is characterized by its specific loci or position in the genome.

The nucleotide sequence information of a gene can have variants and each variant of the gene having a different sequence is referred to as an allelic form or allele of the gene.

A gene may have a single or multiple allelic forms.

How Do Allelic Forms Arise?

Allelic variants arise due to mutations, i.e., changes in the sequence information (Watson 2014). Suppose a gene has a single allelic form having a particular sequence. In course of time, the sequence can get changed due to variety of factors, and the new form with the changed sequence is considered as a new allelic form of...

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Authors and Affiliations

  1. 1.Department of Chemical EngineeringIndian Institute of Technology BombayPowai, MumbaiIndia