What is an allele?

An allele is defined as a variant form of a gene. In genetics, genes can have multiple versions that slightly differ in their DNA sequence, and these variations are what we refer to as alleles. For example, a gene that determines flower color in a plant might have one allele for red flowers and another for white flowers. The presence of different alleles contributes to the genetic diversity within a population and influences traits in organisms.

This concept is fundamental to understanding heredity and the principles of inheritance, as alleles can be dominant or recessive and can interact in various ways to determine an organism's phenotype. The other options do not accurately describe an allele; mutations pertain to changes in the DNA sequence, a specific location on a chromosome refers to a locus, and a collection of genes refers to a genome or gene complex, neither of which captures the idea of a single variant of a gene.