Alternative versions of a gene that code for different variations of a protein are called alleles.

Different alleles may result in the production of different variants of a proteins and be observed as different traits (phenotypes) of an organism, such as petal color.

For each gene, an individual inherits 2 alleles, each inherited from a parent.

An individual's inherited alleles make up its genotype; which may be observed as a visible phenotype (e.g., flower color).