1 The type of diagram shown is a pedigree chart.

Here are the answers to Question 24:

24.1 The type of diagram shown is a pedigree chart.

24.2 There are 3 alleles that control blood groups (I$^A$, I$^B$, and i).

24.3 There are 3 generations represented in the diagram.

24.4 Lina's genotype is I$^A$i. Vusi has blood group O. The only possible genotype for blood group O is ii.
The possible genotype of Vusi is $\boxed{\text{ii}}$.

24.5

• Athi's parents both have blood group O (genotype ii), so Athi's genotype must be ii.
• Athi (genotype ii) and Bob have a child with blood group B. For this child to have blood group B, they must have received an I$^B$ allele from Bob and an i allele from Athi. So, the child's genotype is I$^B$i.
• Athi (genotype ii) and Bob also have Ann with blood group A. For Ann to have blood group A, she must have received an I$^A$ allele from Bob and an i allele from Athi. So, Ann's genotype is I$^A$i.
• Since Bob must contribute both an I$^B$ allele (for his B-group child) and an I$^A$ allele (for Ann), Bob's genotype must be I$^A$I$^B$.

The genotype of Bob is $\boxed{\text{I}^A\text{I}^B}$.

24.6 Co-dominance in blood groups occurs when both I$^A$ and I$^B$ alleles are expressed, resulting in blood group AB. From 24.5, we determined that Bob's genotype is I$^A$I$^B$.
The individual which displays co-dominance is Bob.