Why

Asked by tandonyashika | 25th Jun, 2018, 10:02: PM

Expert Answer:

  • Incomplete dominance is the phenomenon where none of the two contrasting alleles or factors is dominant.
  • The expression of the character in a hybrid or F1 individual is intermediate or a fine mixture of the expression of the two factors.
  • Incomplete dominance is an example of quantitative inheritance where only a single gene pair is involved.
  • The phenotypic ratio of offspring in F2 generation is 1:2:1 which is similar to genotypic ratio.

Example of Incomplete Dominance

  • In Mirabilis jalapa (Four O’ Clock plant) and Antirrhinum majus (Snapdragon plant), there are two types of flowers, red and white.
  • When the two types of plants are crossed, the hybrids of F1 generation bear pink flowers.
  • When the F1 hybrids are selfed, we obtain three types of plants of F2 generation; one with red flowers, one with pink flowers and one with white flowers in the ratio of 1:2:1.
  • The appearance of pink colour is either due to mixing of red and white colours or the expression of a single gene for pigmented flower which produces only pink colour.

Answered by Sheetal Kolte | 28th Jun, 2018, 02:52: PM