Question

In blood group typing in human, if an allele contributed by one parent is ${ I }^{ A }$ and an allele contributed by the other parents is i, the resulting blood group of the offspring will be
(a)A
(b)B
(c)AB
(d)O

Answer 1

Hint: For human blood type there are three different alleles, known as IA, IB, and i. We can call those alleles A (for ${ I }^{ A }$), B (for ${ I }^{ B }$), and O (for i) for simplicity. The alleles of the ${ I }^{ A }$ and the ${ I }^{ B }$ are codominant, and the i allele is recessive.

Complete answer:
The type of human blood is determined by the codominant alleles. An allele is one of several different forms of genetic information present at a specific location on a particular chromosome in our DNA. Because we each inherit one blood type allele from our biological mother and one from our biological father, we each have two ABO blood type alleles. The genotype is a description of the pair of alleles in our DNA. Given that there are three different alleles, the human ABO genetic locus has a total of six different genotypes. The various genotypes that may exist are AA, AO, BB, BO, AB, and OO.
Blood grouping is an example of multiple alleles and codominance where more than one allele gives a single trait like ${ I }^{ A }$, ${ I }^{ B }$, ${ I }^{ O }$ and i. If one parent's allele is ${ I }^{ A }$ and another is i then the offspring will have blood group A because both the allele expresses itself in full, where ${ I }^{ A }$ expresses enzyme for A and i express inactive enzyme.
So, the correct answer is, ‘A’.

Note: The Possible human blood group phenotypes include type A, type B, type AB and type O. Individuals of type A and B may be either heterozygous (${ I }^{ A }i$ or ${ I }^{ B }i$) or homozygous (${ I }^{ A }{ I }^{ A }$ or ${ I }^{ B }{ I }^{ B }$). A blood type O mother can just pass an O allele to her son or daughter. A father whose blood type is AB could pass his son or daughter either an A or a B allele. This couple may have children of either type A blood (O from mother and A from father) or type B blood (O from mother, and B from father).