Question

Which of the following characteristics represent 'Inheritance of blood groups' in humans?

a. Dominance
b. Co-dominance
c. Multiple allele
d. Incomplete dominance
e. Polygenic inheritance

• A. b, d and e
• B. a, b and c
• C. b, c and e
• D. a, c and e

Answer 1

The correct option is B a, b and c

The inheritance of the ABO blood groups in humans is controlled by gene (I) .

Generally, a gene has two alleles, however, the gene (I) has three alleles and this condition is referred to as multiple allelism.

Out of the three alleles, A and B alleles are dominant and the ‘i’ allele is recessive.

In heterozygous conditions, such as (IAi or IBi), the alleles A and B are expressed but not allele i. Hence, this is an example of dominance.

ABO blood groups are also an example of codominance.

Codominance occurs when both alleles are dominant and express independently, as in the case of the AB blood type (IAIB) in humans.