The genetic structure that can exist as either dominant or recessive is referred to as alleles. Alleles are different forms of a gene that can produce variations in traits. For instance, the gene for flower color may have a dominant allele (which dictates a specific color) and a recessive allele (which may result in a different color only when both alleles are recessive). In genetics, the expression of an organism’s phenotype (observable traits) relies on the combination of alleles inherited from its parents.