1. DO NOW
In a population of trolls the trait for snaggle toes (T) is dominant and the trait for straight toes is recessive (t). Also, the trait for blue hair is dominant (B) and the trait for green hair is recessive. Two heterozygous trolls (for both traits) get married. What is the probability their offspring look like them? Draw the Punnett squares and write out the phenotypic ratios.

3. Review from Worksheet
In a sheep, assume that spotted skin (S) is dominant over non-spotted skin (s) and that wooly hair (W) is dominant over non-wooly hair (w). Cross a marriage between a heterozygous spotted, non-wooly sheep with a wooly-haired, non-spotted sheep. Give the phenotypic ratio of the offspring.

4. Today’s Lesson
Objective: I can explain the function of polygenic, incomplete dominance, and codominance in inheritance.
Essential Question: What happens when inheritance patterns go beyond Mendel’s Law of Dominance?

5. Notes

6. Review Mendel Two types of alleles? Dominant and recessive
Each gene requires 2 alleles
Three allele combinations?
Homozygous Dominant (HH)
Heterozygous (Hh)
Homozygous recessive (hh)
Three Mendel's laws of inheritance
Law of Dominance
Law of Segregation
Law of Independent Assortment

7. Mendel Review Monohybrid cross Dihybrid cross Mono = one
Examine inheritance of one trait
Punnett square with 4 grid boxes
Grid boxes have 2 alleles (1 trait)
Di = two
Examine inheritance of two traits
Punnett square with 16 grid boxes
Grid boxes contain 4 alleles (2 traits)

8. Non-Mendelian Genetics
There are a few types in inheritance patters that go beyond what Mendel discovered:
Incomplete Dominance
Codominance
Polygenetic

9. Incomplete Dominance rr RR Rr Genotype = heterozygous
Neither allele has complete dominance over the other, which results in a third phenotype.
Heterozygous phenotype = mix/blend of the two parent alleles rr
Tricks to help students remember: The two phenotypes meet in the middle of or intermediate = incomplete dominance. RR Rr
Homozygous dominant
Homozygous recessive
Heterozygous
RED
WHITE
PINK

10. Incomplete Dominance W W RW R RW RW RW R
Using Mendel's laws of segregation and independent assortment, cross a Red flower (RR) with a white flower (WW)
What are the possible genotypes and phenotypes of the offspring?
Geno: 4 heterozygous RW
Pheno: 4 pink flowers
Your
turn W W RW R RW RW RW R

11. Incomplete Dominance R W RR R RW RW WW W
Using Mendel's laws of segregation and independent assortment, two pink flowers RW
What are the possible genotypes and phenotypes of the offspring?
Geno: 1 RR: 2 RW: 1WW
Pheno: 1 Red, 2 Pink and 1 White
Your
turn R W RR R RW RW WW W

12. Codominance Heterozygous genotype
Co = together
Heterozygous genotype
Neither allele is dominant nor recessive
Phenotype- Both alleles fully and separately expressed (visible)
Erminette

13. Codominance
A red colored flower (RR) is crossed with a white colored flower (WW). 
Use Mendel's laws of segregation and independent assortment to complete the Punnett square.
What are the possible genotypes and phenotypes of the offspring?
 Genotype: 4 heterozygotes (RW) 
Phenotype: 4 red and white flowers
Your
turn W W RW
Use collaborative strategies while having students answer the last question.
Answer: 1 red flower, 1 white flower and 2 red and white flowers R RW R RW RW

14. Polygenic Inheritance
What do you think poly- means?
What do you think –genic means?
Polygenic inheritance is expressed when multiple genes each make a small contribution to the overall phenotype.   
Allows for more than 2 or 3 variations in expressed phenotypes
For example, skin color ranges from very fair 
     to very dark skin shades.  
At least 378 genes are involved in determining skin color.

15. Polygenic Inheritance
Punnett squares are complicated for polygenic inheritance.
Other factors are involved with polygenic traits.
What else can influence skin color?
Environment & nutrition
Other polygenic traits:
Height, eye color, hair color and body shape

16. Polygenic Inheritance
Which person in the picture above received more dominant alleles for pigment?
Which received more recessive alleles for pigment?
Which traits do you think are more prominent?
Describe the possible genotypes for the man on the right.

17. Lab Stations
We will complete two activities to simulate the inheritance patterns we discussed today.
Don’t Lose your Marbles – Codominance & Incomplete Dominance
Eye Color – Polygenic Inheritance
The class will be split in half
Each doing a different lab
20 minutes at each lab
You will have directions at each station.
Read and follow the directions completely.

18. Don’t Lose Your Marbles
Materials:
Simulation 1: Cups #1 - #3 Beads
Simulation 2: Cups #4 - #6 Dye
Clean up:
Separate beads back into their original cups
Pour out & rinse cup #6 (back sinks)
Refill cup #4 with blue dye up to the line
Refill cup #5 with yellow dye up to the line
Wipe up your desk if needed .
1 Cup with blue beads – labeled #1
1 Cup with yellow beads – labeled #2
1 Empty clear cup – labeled #3
1 Cup of blue dye – labeled #4
1 Cup of yellow dye - labeled #5
1 Empty clear cup – labeled #6
Allele
Genotype(s)
Phenotype
Cup 1
Cup 2
Cup 3
Allele
Genotype(s)
Phenotype
Cup 4
Cup 5
Cup 6

19. Eye Color & Polygenic Inheritance
Materials:
Part 1: Spectrum
Answer questions 1 & 2 on the back of your student sheet
Part 2: Determining the parent’s eye color
Part 3: Determining the offspring's eye color
Answer questions 3 & 4 on the back of your student sheet
Clean up:
Empty & rinse well plate
Empty all chips from “Mother” & “Father” bags
Make sure there are 6 blue and 6 yellow chips in the “Male” bag
Make sure there are 6 blue and 6 yellow chips in the “Female” bag
Place all materials in the basket
Bag labeled “Female” with 6 Blue chips and 6 yellow chips
Bag labeled “Male” with 6 blue chips and 6 yellow chips
Dropper bottle with blue dye
Dropper bottle with yellow dye
Bag Labeled “Mother”
Bag Labeled “Father”
Well plate
White Paper

20. Lab Stations – Expectations
When you are done..
Questions – ask three before me
Stay at your desk area
Low voice levels
Clean up your station according to the directions in your basket.
Complete lab analysis questions or practice problems.
Complete vocabulary (old or new)
Work on any late/missing work.

21. Don’t Lose Your Marbles
Materials:
1 Cup with blue beads – labeled #1
1 Cup with yellow beads – labeled #2
1 Empty clear cup – labeled #3
1 Cup of blue dye – labeled #4
1 Cup of yellow dye - labeled #5
1 Empty clear cup – labeled #6
Allele
Genotype(s)
Phenotype
Cup 1
Cup 2
Cup 3
Which simulation is codominance?
How do you know?
Which simulation is incomplete dominance?
Allele
Genotype(s)
Phenotype
Cup 4
Cup 5
Cup 6
How do you know?

22. Eye Color & Polygenic Inheritance
Materials:
Part 1: Spectrum
Describe the spectrum
How does the dominant allele impact the phenotype?
Part 2: Determining the parent’s eye color
Part 3: Determining the offspring's eye color
How did the phenotype of your offspring compare to the parents?
Compare the results from this lab to real life.
Bag labeled “Female” with 6 Blue chips and 6 yellow chips
Bag labeled “Male” with 6 blue chips and 6 yellow chips
Dropper bottle with blue dye
Dropper bottle with yellow dye
Bag Labeled “Mother”
Bag Labeled “Father”
Well plate
White Paper

23. Let’s Practice
4. In fish of the species Perissodus microlepis, some individuals have mouths that open to the right and some individuals have mouths that open to the left. The direction of the mouth opening is a genetic trait controlled by a single gene. The allele for a right-opening mouth (R) is dominant to the allele for a left-opening mouth (r). If two fish heterozygous for the mouth trait are crossed, what is the expected ratio of phenotypes in the offspring?
A. 1 right-opening mouth : 3 left-opening mouth
B. 2 right-opening mouth : 2 left-opening mouth
C. 3 right-opening mouth: 1 left-opening mouth
D. 4 right-opening mouth: 0 left-opening mouth

24. What about our genes? Closing
Explain how phenotype is affected by incomplete dominance.
Explain how phenotype is affected by codominance.
Explain how phenotype is affected by polygenic traits.
Identify and explain how Mendel's Laws  play a role in Non-Mendelian inheritance.
Enforce the use of genetic vocabulary in each student response.
Example: student says heterozygous is one capital letter and one lower case letter. Teacher reinforcement example: “What does the capital letter represent?” Correct response: “A dominant allele.”

25. Exit Ticket
Clear your desk

26. 1. Hitchhiker's thumb (H) is dominant to no hitchhiker's thumb (h)
1. Hitchhiker's thumb (H) is dominant to no hitchhiker's thumb (h). A woman who does not have hitchhiker's thumb marries a man who is heterozygous for hitchhiker's thumb. What is the probable genotypic ratio of their children? 
0% Hh: 100% hh
50% Hh: 50% hh
75% Hh: 25% hh
100% Hh: 0% hh B.

27. 2. Not all traits follow the Mendelian inheritance patterns
2. Not all traits follow the Mendelian inheritance patterns. Some traits are determined by the combined effect of more than one pair of genes. Height is controlled by at least three genes with six alleles. If you are dominant for all of the alleles for height, then you will be very tall. There is also a wide range of skin colors across people. The result is the perception of continuous gradation in the expression of these traits. This is type of trait is referred to as A. epistasis inheritance B. polygenic inheritance C. intermediate inheritance D. non-Mendelian inheritance

28. 3. The hair on a baby’s head is likely to be wavy or gently curled when a straight-haired person and a curly-haired person have a child. The phenotypic result is a blend between the phenotypes of the homozygous parents. Which pattern of inheritance does a wavy hair baby show?
A. Codominance
B. Incomplete dominance
C. Intermediate inheritance
D. Traits passed between the sex chromosomes