Question

The phenotypic and genotypic ratio in incomplete dominance is

• A. 1:2:1
• B. 9:3:3:1
• C. 3:1
• D. 9:7

Answer 1

The correct option is A 1:2:1

Incomplete dominance is a form of intermediate inheritance in which one allele for a specific trait is not completely dominant over the other allele. This results in a third phenotype in which the expressed physical trait is a combination of the dominant and recessive phenotypes. In incomplete dominance, only a single gene pair is involved. F${}_2$ phenotypic ratio is 1:2:1 and is similar to genotypic ratio.

For example: Incomplete dominance is seen in cross-pollination experiments between red and white snapdragon plants. The dominant allele that produces the red colour is not completely expresses over the recessive allele that produces the white colour. The resulting offspring are pink.