1. Codominance The expression of both alleles
Neither one of the alleles are dominant or recessive, and is expressed in the offspring.
Ex. - In some chickens, alleles for feather color are codominant.

2. Codominance Alleles are written with superscripts. Genotype = FB FB
Phenotype = Black
Genotype = Fw Fw
Phenotype = White

3. Codominance
FB FB Fw
FBFW
FBFW
FBFW
FBFW

4. Codominance
Other example of Codominance.
Shorthorn Cattle

5. Environmental Influences
The genetic make-up of an organism only determines the potential of an organism.

6. Environmental Influences
External Influences
Temperature
Light
Nutrition

7. Environmental Influences
Internal Influences
Internal body functions
Hormones
Age