1. Incomplete Dominance Codominance
A Quick Review

2. Incomplete Dominance
A third (new) phenotype appears in the heterozygous condition.

3. Incomplete Dominance Example 1
In blue blahblah bird & a white blahblah bird produces offspring that are silver show the cross between two heterozygous birds.
B W
GENOTYPES:
- BB (1); BW (2); WW (1) BW B W BB WW BW
PHENOTYPES:
Blue (25%); Silver (50%); White (25%)

4. Incomplete Dominance Example 2
In blue blahblah bird & a white blahblah bird produces offspring that are silver show the cross between a blue bird and white bird.
B B
GENOTYPES:
- BW (4) BW BW W
PHENOTYPES: BW BW
- Silver 100%

5. Codominance
The heterozygous condition, both alleles are expressed equally.
In some chickens, the gene for feather color is controlled by codominance. The heterozygous phenotype is known as erminette (spotted chickens).

6. Codominance Example 1
A white chicken is crossed with erminette (spotted chickens).
W W
GENOTYPES:
- BW (2) and WW (2) BW BW B W
PHENOTYPES: WW WW
- spotted chickens 50% and
White 50%

7. Multiple Alleles There are more than two alleles for a trait
A and B are codominant
AA = Type A
BB = Type B
AB = Type AB
A and B are dominant over O

8. Problem: Multiple Alleles
Show the cross between a mother who has type O blood and a father who has type AB blood.
O O
GENOTYPES:
- AO (2) BO (2) A B AO BO
PHENOTYPES:
- type A (50%); type B (50%)

9. Multiple Alleles Example 1
Show the cross between a mother who has type AO blood and a father who has type AB blood.
A O
GENOTYPES:
- AO (2) BO (1) AB (1) A B AA BO AO AB
PHENOTYPES:
type A (50%); type B (25%)
Type AB 25%

10. Multiple Alleles Example 2
Show the cross between a mother who has type AB blood and a father who has type OO blood.
A B
GENOTYPES:
- AO (2) BO (2) O AO BO
PHENOTYPES:
type A (50%); type B (50%)