Question

In case of incomplete dominance, F${}_2$ generation has

• A. Genotypic ratio equal to phenotypic ratio
• B. Genotypic ratio is 3:1
• C. Phenotypic ratio is 3:1
• D. None of the above

Answer 1

Answer: (A)

Genotypic ratio equal to phenotypic ratio

Incomplete dominance is a form of intermediate inheritance in which one allele for a specific trait is not completely expressed over its paired allele. This results in a third phenotype in which the expressed physical trait is a combination of the dominant and recessive phenotypes.
Incomplete genetic dominance is similar to, but different from co-dominance. In co-dominance, an additional phenotype is produced, however both alleles are expressed completely. Co-dominance is observed in AB blood type inheritance.
Example: Incomplete dominance is seen in cross-pollination experiments between red and white snapdragon plants. The allele that produces the red color (R) is not completely expressed over the recessive allele that produces the white color (r). The resulting offspring are pink. The genotypes are: (RR) Red, (rr) White, and (Rr) Pink.
In case of incomplete dominance, F${}_2$ generation has genotypic ratio equal to phenotypic ratio.