Download presentation
Presentation is loading. Please wait.
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%)
Similar presentations
© 2025 SlidePlayer.com. Inc.
All rights reserved.