Chapter 11.2, Problem 6MI

Summary Introduction

To determine:

Different phenotypes obtained by crossing the given blood types.

Introduction:

Codominance: It is a condition, in which two alleles are equally dominant. In this condition, the resultant phenotype is the cumulative expression of both the alleles. In human blood grouping, the type A and type B allele are codominant and allele for blood type O is recessive.

Explanation of Solution

In the human blood group, if the allele for both A and B blood types are present, then the resultant blood type is AB. IN case of homozygosity, the allele will have a single type of blood type, so, if the person is homozygous for allele A, then the blood type will be A, similarly for homozygosity for blood B and O occurs. In case, the allele of A or B blood type is present with recessive allele, then the respective dominant allele (type A or type B) will be expressed.

Possible Genotype combination	Phenotype
A and A	A
A and B	AB
A and O	A
B and B	B
B and O	B
O and O	O