Question

Suppose A is an abstract class, B is a concrete subclass of A, and both A and B have a no-arg constructor Which of the following is correct? (Select all that apply)

A. Bb=new BO:
B. Bb=new AO;
C Aa=new AO;
D. A a= new BO:
E. None of that

Answer 1

The ABO blood groups in humans, determined by IA, IB, and i alleles, display codominance and multiple alleles when a child inherits the AB blood type (IAIB) from heterozygous parents, causing both A and B antigens to be equally expressed.

Step-by-step explanation:

The ABO blood groups are an important genetic system in humans for blood type determination. They're controlled by three alleles: IA, IB, and i. The IA allele encodes the A blood group antigen, IB encodes B, and i encodes O, with both A and B being dominant over O. When a heterozygous blood type A parent (IAi) mates with a heterozygous blood type B parent (IBi), their offspring have a chance of displaying one of the four blood types, depending on the combination of alleles they inherit.

Specifically, there is a 25% chance (one quarter of their offspring) that they will exhibit the AB blood type (IAIB), where both the A and B antigens are expressed equally. This manifestation is due to codominance, where both alleles in the heterozygous state are fully expressed, and multiple alleles, since there are more than two allele options (IA, IB, i) for a single genetic locus.

To summarize, the ABO blood group system is an example of a trait that is determined by multiple alleles and codominance, not incomplete dominance, since both IA and IB are fully expressed when combined, resulting in the AB phenotype.