Same chapter3 marksDifficulty: Medium
Explain a test cross and state what it is used for.
Principles of Inheritance and Variation
3 marksDifficulty: Medium
Explain incomplete dominance and codominance with one example of each.
Original Khojo Papers practice question — not from a past board paper.
Answer
In incomplete dominance neither allele is fully dominant and the heterozygote shows an intermediate phenotype, as in the pink flowers of the heterozygous snapdragon. In codominance both alleles are fully expressed in the heterozygote, as in human blood group AB, where both the A and the B antigens appear.
No citable source has been recorded for this record. Treat it as practice material, not as fact.
Explanation
In both cases the phenotypic ratio of the F2 becomes 1 : 2 : 1 rather than 3 : 1.
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