Why do blood groups show codominance?
Blood groups show codominance because both alleles can express themselves fully without masking each other.
Key Idea
| Term | Meaning |
|---|---|
| Codominance | Both alleles express equally |
| Alleles (IA, IB, i) | Control blood group types |
Genetic Basis
| Genotype | Blood Group |
|---|---|
| IAIA or IAi | A |
| IBIB or IBi | B |
| IAIB | AB |
| ii | O |
Why Codominance
| Reason | Explanation |
|---|---|
| No Masking | IA and IB both express |
| Equal Expression | Both antigens appear on RBC surface |
| Distinct Phenotype | AB shows both A and B traits |
Stepwise Understanding
Individual inherits IA from one parent and IB from another
Both alleles remain active
Both A and B antigens are produced
Blood group becomes AB
Important Concept
In codominance, both traits are fully visible, unlike blending or masking.
Real Insight
AB blood group is clear example where two different traits are expressed together, not mixed or hidden.
So blood groups show codominance because both alleles express equally at the same time.