Multiple alleles are non-mendelian inheritance patterns in which more than two alleles code for the same trait in a species.
Multiple alleles can have more than two phenotypes.
When numerous alleles are involved in the expression of a trait, a variety of dominance patterns emerge. In some circumstances, one of the alleles is entirely recessive to others and is disguised by any dominant alleles. Other alleles can be co-dominant, displaying their traits in their phenotypes in equal amounts.