Co-dominance | A | B |
A | AA | AB |
B | AB | BB |
Incomplete dominance
| R | r |
R | RR | Rr |
r | Rr | rr |
Inheritance of AB blood group in human follows co-dominance while inheritance of flower colour in Mirabilis jalapa follows incomplete dominance. Co-dominance is a form of dominance where alleles of a gene pair in a heterozygote are fully expressed. In AB blood group, both A and B alleles are fully expressed. Therefore, an individual has neither A nor B blood group but AB blood group.
Incomplete dominance is a form of inheritance in which one allele for a specific trait is not completely expressed over its paired allele. In Mirabilis jalapa, plants with Rr genotype are not red (dominant allele) but pink (a third phenotype produced as a result of a combination of other two phenotypes).
So, the correct option is 'Inheritance of AB blood group in man and flower colour in Mirabilis jalapa'.