How are alleles and genes related?

1 Answer
Dec 12, 2014

An allele is a form of a gene. For example, in humans, the ABO gene for the ABO blood group is located on chromosome 9, ( and has three alleles (forms), A, B, and O. A person can inherit only two alleles for the ABO blood group, one from each parent. The two alleles that a person inherits determines that persons ABO blood group.