AGB 121: Principles of Animal Genetics and Population Genetics (2+1)

Incomplete dominance examples

INCOMPLETE DOMINANCE / SEMIDOMINANCE EXAMPLE

• In the heterozygous condition, the total product is intermediate between that of the dominant and recessive alleles.
• For example
  • In four- O’- clock plants (Mirabilis Jalapa) and Snapdragon (Antirrhinum majus), when red-flowered plants are crossed with white - flowered plants, the heterozygotes F₁ produce pink flowers. The phenotypic ratio for the monohybrid cross becomes 1:2:1 instead of 3:1.

  

 To view "Incomplete Dominance Animation"

• Another interesting example is the Blue Andalusian chickens.
• These breeds were developed by crossing black chicken of a certain strain with a white splashed white chicken (White with black splashes).
• The offspring are blue. When crossed together, these blue chicken produce black, blue and white in the ratio of 1:2:1.