Question

Expression of different genes for different traits may show dominance, incomplete dominance, or co-dominance. Write about expression of such genes with examples for one of the above modes.
[0.5cm]

Hint:

Gene expression patterns like dominance, incomplete dominance, and co-dominance reveal the diversity of inheritance in organisms.

Answer 1

Dominance: A dominant allele masks the expression of a recessive allele. For example, the tallness allele (T) in pea plants is dominant over the dwarfness allele (t). A heterozygous plant (Tt) shows the tall phenotype.

Incomplete Dominance: The heterozygous phenotype is an intermediate blend of the parental traits. For instance, crossing a red-flowered snapdragon (RR) with a white-flowered snapdragon (rr) produces pink flowers (Rr).

Co-dominance: Both alleles express themselves equally and simultaneously. A classic example is the human ABO blood group system, where alleles I_A and I_B are co-dominant, resulting in the AB blood group.

Quick Tip: In dominance one allele hides the other, in incomplete dominance traits blend, and in co-dominance both traits appear together.