Question

A boy has blood type MN with a genotype of LMLN. His red blood cells possess both the M antigen and the N antigen. What is the relationship between his two alleles for this gene?

Answer 1

Answer:

Co-dominance

Explanation:

Co-dominance is a genetic phenomenon where two versions of a gene called alleles are neither recessive nor dominant to one another. Hence, the phenotypic expressions encoded by both alleles are expressed simultaneously.

In this case of the MN blood system, the boy has a LMLN genotype and expresses both genes M and N in his red blood cells. Hence, alleles M and N are said to be codominant to one another i.e. M is not dominant or recessive to N and vice versa.