PATHOLOGY

Detailed explanation-1: -Blood type in humans is normally controlled by multiple alleles but not multiple genes. Human blood type or ABO blood type is controlled by the ABO gene, which has three distinct alleles (multiple alleles), a, b, and I.

Detailed explanation-2: -A polygenic trait is a characteristic, such as height or skin color, that is influenced by two or more genes. Because multiple genes are involved, polygenic traits do not follow the patterns of Mendelian inheritance.

Detailed explanation-3: -An excellent example of multiple allele inheritance is human blood type. Blood type exists as four possible phenotypes: A, B, AB, & O. There are 3 alleles for the gene that determines blood type.

Detailed explanation-4: -The gene responsible for the ABO blood group system is I. This gene exists in three allelic forms-IA, IB and i. IA and IB are dominant alleles and i is the recessive allele. Since, three alleles for ABO blood group are found in a population, it is an example of multiple allelism.

Detailed explanation-5: -The best characterized example of multiple alleles in humans is the ABO blood groups, discussed in the Non-Mendelian Inheritance concept. Other human traits determined by multiple alleles would be hair color, hair texture, eye color, built, physical structures, etc.