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प्रश्न
Write a note on multiple alleles considering examples of human blood groups.
उत्तर
- More than two alternative forms (alleles) of a gene in a population occupying the same locus on a chromosome or its homologue are known as multiple alleles.
- ABO blood group system in humans is an example of multiple allelism because gene I exists in three allelic forms IA, IB and IO.
- Here, allele IA codes for type A blood, allele IB codes for type B blood and allele IO codes for type O blood.
- Allele IO is recessive to the alleles IA and IB.
- Thus, with these three alleles, we can have 6 different genotypes and 4 different phenotypes for blood groups.
| Genotype | Phenotype (Blood group) | |
| 1. | IA IA or IA IO | Type A |
| 2. | IB IB or IB IO | Type B |
| 3. | IA IB | Type AB |
| 4. | IO IO | Type O |
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| Column 'A' (Gene interactions) |
Column 'B' (Example) |
|
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