Chapter 11, Problem 14A

Summary Introduction

Introduction :

The human blood group is determined by a gene I. It has three alleles I^A, I^B, and i. If a person having alleles I^A and I^B, both genes are express completely resulting into a new phenotype. This reflects the alleles I^A and I^B are codominant.

Answer to Problem 14A

Correct answer :

The correct answer is option (B) is codominance and multiple alleles.

Explanation of Solution

Explanation/justification for the correct answer :

Option (B) is codominance and multiple alleles.The human blood group is determined by a gene I. It has three alleles I^A, I^B and i (multiple alleles). If a person having alleles I^A and I^B are present, thenboth genes are express completely. The alleles I^A and I^B are codominant.Thus, the correct answer is option (B).

The explanation for the incorrect answer :

Option (A) incomplete dominance and codominance. In incomplete dominance both alleles blend to give new phenotype. Thus, this is an incorrect option.

Option (C)incomplete dominance and multiple alleles. A human blood group type is a case of multiple alleles but not incomplete dominance. Thus, this is an incorrect answer.

Option (D) codominance and epistasis. Human blood group types is a case of multiple allele inheritance pattern but not epistasis. Thus, this is an incorrect answer.