1. Pick up your plickers card and worksheet BEFORE the bell rings
Bell Work
Pick up your plickers card and worksheet BEFORE the bell rings

2. Incomplete Dominance vs. Codominance
Mrs. Stewart
Biology

3. Standards
CLE Compare different modes of inheritance.

4. Lesson Objectives
Correctly create and analyze the punnett square results from incomplete and codominant crosses
Can identify scenarios of incomplete dominance and codominance successfully

5. Three types of dominant relationships for alleles
Complete dominance
Monohybrid crosses
Dihybrid crosses
Incomplete dominance
Codominance

6. Complete Dominance Standard dominant vs recessive relationship
If dominant allele is present – you get dominant phenotype
If dominant allele is not present – you get recessive phenotype
Ex: Tongue Rolling (RR or Rr = can roll tongue, rr = can’t)

7. Incomplete dominance One is not completely dominant over the other
Instead, heterozygotes will have a blending of the dominant and recessive traits

8. Incomplete Dominance
Heterozygous = Blend/combo of the parent phenotypes
Phenotype = number of horns
3 possible phenotypes = incomplete dominance

9. Incomplete Dominance - Alleles
RR = red
Rr = pink
rr = white
If you cross a red flower with a pink flower, what percentage of the offspring will be white? Red?

10. Codominance
Both alleles for a gene are expressed in the heterozygotes – simultaneously (at same time)
Neither allele is dominant and they do NOT blend together

11. Codominant Alleles
Since both are dominant and both are seen, we typically write them as different capital letters.
WW = white horse
GG = gray horse
WG = Apaloosa horse (white horse with gray spots)

12. Plickers Practice
Snapdragons are flowers that can be either white, red or pink. How is color inherited?
A = complete dominance
B = incomplete dominance
C = codominance
D = none of the above

13. Plickers Practice
Cross a pink snapdragon (Rr) with a pink snapdragon (Rr). What is the probability that the offspring will be white?
A = 100%
B = 75%
C = 25%
D = 0%