Question

Phenotypic and genotypic ratio is similar in case of ________________.
(A) Complete dominance
(B) Incomplete dominance
(C) Over dominance
(D) Epistasis

Answer 1

Hint: The morphological or external appearance of an organism that reflects a particular character is known as Phenotype. The genotype represents the genetic constitution of an organism. The checkerboard method or Punnett square grid is a method used to determine the phenotype ratio. Phenotype ratio is also known as the Basic ratio or Mendelian ratio.

Complete answer:
Complete dominance: It is observed when two different unit factors are there in an individual but only one unifying factor is expressed. The factor which expresses itself is known as a dominant factor and the factor which fails to express itself is called the recessive factor. In complete dominance, the phenotypic ratio and the genotypic ratios are different i.e. $3:1$ and $1:2:1$ respectively.
Incomplete Dominance: Both Dominant and recessive factors are present in the incomplete dominance although the dominant factor is unable to express completely which results in an Intermediate type of generation. Both phenotypic and genotypic ratio is the same in the Incomplete dominance and i.e. $1:2:1$
Epistasis: The phenomenon where a gene inhibits the expression of a non-allelic gene is known as Epistasis.

Therefore, the correct option is (B) Incomplete dominance.

Note:
Complete dominance is based on ${F_1}$ generation. In some organisms, ${F_1}$ generation is different from both the parents. Examples of Incomplete dominance are Flower color in Mirabilis jalapa, Flower color in Antirrhinum majus, and Feather color in Andalusian Fowls. Incomplete dominance was first discovered in Mirabilis jalapa by Correns. Three different types of plants are found in Mirabilis on the basis of flower colour such as red, white, and pink.