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...
- Futuyma, D. (2006). Evolutionary biology (3rd ed.). New York: W.H. Freeman.Google Scholar
- Hartl, D. (2012). Essential genetics: A genomics perspective (6th ed.). Sudbury: Jones & Bartlett Learning.Google Scholar
- Hartl, D., & Clark, A. (2007). Principles of population genetics (1st ed.). Sunderland: Sinauer Associates.Google Scholar
- Snustad, D., & Simmons, M. (2003). Principles of genetics (3rd ed.). New York: Wiley.Google Scholar
- Watson, J. (2014). Molecular biology of the gene (7th ed.). San Francisco: Pearson Education.Google Scholar