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Principles of Inheritance and Variation — BIOLOGY STD 12 Science — Question

Rajasthan BoardEnglish MediumSTD 12 ScienceBIOLOGYPrinciples of Inheritance and Variation4 Marks
Question
Explain co-dominance in humans with the help of example.
✓

Answer

→ Co-dominance is a phenomenon in which two alleles express themselves independently when present together in an organism.
→ Example: ABO Blood Group
→ It is the inheritance in which both alleles of a gene are expressed in a hybrid. E.g. ABO blood grouping inhuman.
→ ABO blood groups are controlled by the gene I.
→ This gene controls the production of sugar polymers (antigens) that protrude from plasma membrane of RBC.
→ The gene I has three alleles IA, IB & i.
→ IA and IB produce a slightly different form of the sugar while allele i doesn't produce any sugar.Image
→ When I and I are present together, they both express their own types of sugars. This is due to co-dominance.

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