1. Co-dominance and Incomplete Inheritance
1.3 – Characteristics and Inheritance Page 21

2. Incomplete and Co-dominance

3. Incomplete Dominance
When neither allele is dominant and they blend together to form a new phenotype.
Each genotype has a different phenotype
The heterozygous phenotype will be intermediate/blended between the two homozygotes.
We use upper case letters for each colour
eg: W = white and B= black therefore WB = grey

4. Example
When red flowers are crossed with white flowers all of the offspring have pink flowers. What percent of the offspring will be red, white and pink if we cross two pink flowers?

5. Draw a punnet square to determine the % of offspring when two pink flowers are crossed
R = red
25% R RR RW
W = white
25% W RW WW
50%
RW = pink

6. Co-dominance
Neither allele is dominant and both are expressed in the phenotype of the heterozygote

7. Example
When white bears mate with black bears, all the offspring have black and white spots.

8. What type of offspring will be produced if a black bear and a spotted bear are mated?
B = black
50% B BB BB
W = white 0% W BW BW
BW = spots
50%

9. Complete Questions from your Genetics Booklet on pages 20,21,22
This is due Wednesday