1. Warm ups: What is a sex linked disorder?
What chromosome are these genes usually on? ( X or Y)
If you were a male, what two chromosomes would you have?
a. XX B. YY C. XY

2. Incomplete dominance and Co-dominance in Genetics

3. Lets look at Incomplete Dominance first!!!
Incomplete dominance is like the genes sharing the dominance. You get a mixing or blending of the dominant trait.

4. Incomplete dominance
Incomplete dominance – when there are two dominant traits that don’t have dominance over each other. This results in a combined phenotype.
It’s like a “blending” of the two dominant genes, both traits are expressed. (sharing dominance)
+ =
White Red Pink

5. Incomplete dominance 3. Examples:
Red flower color (R) and White flower color (W) = Pink flowers (RW)
b. Red flowers (R) and Blue flower color (B) = Purple flower color (RB)
+ =
+ =

6. c. When you have a purebred red; the genotype is RR
d. When you have a purebred white; the genotype is WW
e. When you have hybrid flower (RW) the resulting color is PINK!! (both share dominance)

7. Examples of Incomplete Dominance
Skin color
Flower color
Fur color
Short fur or long fur

8. INCOMPLETE DOMINANCE PUNNETT SQUARES PRACTICE PROBLEMS
1. A red flowered is crossed with a white flowered . (R = red, W = white)
R R RR
Red flower = _____
White flower = ____ WW W R W R W
____ % white
____ % red
____ % pink
____ % heterozygous
____ % homozygous W
100 W R R W
100

9. 2. A blue flowered rose is crossed with a purple flowered rose
2. A blue flowered rose is crossed with a purple flowered rose. (B = blue, R = red)
B B BB
Blue flower = _____
purple flower = ____ BR B B B B B 50
____ % blue
____ % red
____ % purple
____ % heterozygous
____ % homozygous B 50 R R R B 50 50

10. Now lets talk about Co-dominance in Genetics
In Co-dominance, you see both dominance traits.

11. Co-Dominance
Co-dominance – when two dominant traits are shown in the offspring.
Both traits appear at the same time, but not mixed or blended together. =
White Red Red and white
+ =

12. Co - dominance 3. Examples:
Example: Red flower color (R) and White flower color (W) = Red and White flowers (RW)
b. Example: Yellow flowers (Y) and Blue flower color (B) = Yellow and Blue flower color (YB)
+ =
+ =

13. Co - DOMINANCE PUNNETT SQUARES PRACTICE PROBLEMS
1. A red flowered is crossed with a white flowered . (R = red, W = white)
R R RR
Red flower = _____
White flower = ____ WW W R W R W
____ % white
____ % red
____ % red and white
____ % heterozygous
____ % homozygous W
100 W R R W
100

14. Exit slip
What type of dominance creates in a blending or sharing of the genes?
What type of dominance creates an offspring that shows both dominant traits.