Red blood cells carry antigens on their surfaces coded for by alleles of the gene represented by the letter I. The allele IA is dominant to i and produces antigen A on the surface of red blood cells. The allele IB is also dominant to the i allele and produces antigen B on the surface of red blood cells. The i allele does not produce surface antigens.
What type of pattern of inheritance is represented by the genetics of human blood types?
I. IA and IB show incomplete dominance because both alleles are partially expressed in blood type A and B.
II. The human blood types are an example of polygenic traits with four possible phenotypes: A, B, AB, O.
III. IA and IB show codominance because both alleles are equally expressed in blood type AB.
IV. The human blood type gene is an example of a gene with multiple alleles: IA, IB, i.
a. I and IV are correct
b. I, III and IV are correct
c. II, III, and IV are correct
d. I and II are correct