Question

1. Explain how blood types can display multiple allelism. In other words, how can there be so many different blood types?

2. What blood sample(s) could be given to a patient with type A- blood? What would occur if this patient was given an incompatible blood type?

Answer 1

1) There are three alleles for blood group:

iA, iB, iO.

iA and iB are dominant over iO allele.

iA and iB are codominant to each other.

Presence of Rh factor makes positive blood group whereas absence of Rh makes negative blood group.

Now different type of blood group:

*when genotype is iAiO or iAiA, then blood group is A. It if further divided into A+ orA- based on the presence or absence of Rh factor.

* when genotype is iBiO or iBiB then blood group is B. It if further divided into B+ or B- based on the presence or absence of Rh factor

*when genotype is iOiO , then blood group is O. It if further divided into O+ or O- based on the presence or absence of Rh factor.

Question 2)

A- blood group person has antigen A on its blood cell and there is no Rh factor. There is anti- B antibody present in the blood of A- blood group person. That's why blood group of A- and O- can be given to that person.

If the person is given with incompatible blood group, then there is agglutination reaction occur between antigen and antibody of donor and receiver blood group. This leads to clumping of RBC.