Course Content
Classification I
The Cell
Cell Physiology
Nutrition in Plants and Animals
Transport in Plants and Animals
Gaseous Exchange
Respiration
Excretion and Homeostasis
Classification II
Ecology
Reproduction in Plants and Animals
Growth and Development in Plants and Animals
Final Exam
BIOLOGY

Incomplete dominance

Incomplete dominance; no allele completely dominates the other i.e. all alleles express themselves equally.

In genetic crosses involving incomplete dominance, two different capital letters are used to represent the two genes.

Example;

in some plants such as Mirabilis jalapa (4 o’clock plant) a cross between red and white flowered plants results in F1 generation with all the plants bearing pink flowers thus showing blending of colour. Self-pollinating the F1 individuals give phenotypic ratio of 1 red: 2 pink: 1 white. Let R represent the gene for red flower colour. Let W represent the gene for white flower colour.

Incomplete dominance
F1 generation

Selfing the pink flowered plants

Incomplete dominance F2