1. Punnett Genetics
Dr. Nichols
Coronado HS

2. Punnet Square Created by Punnet
Used to predict possible outcomes of crosses

3. Problem #1 (together)
Nn x NN
Genotype ratio:
Phenotype ratio:

4. Problem #2
Aa x aa
Genotype ratio:
Phenotype ratio:

5. Problem #3 (on your own)
Tt x Tt
Genotype ratio:
Phenotype ratio:

6. Problem #4 Cross two plants that are heterozygous for green pods
Genotype ratio:
Phenotype ratio:

7. Problem #5
Cross a plant that is heterozygous for axial flowers with a plant that has terminal flowers.
Genotype ratio:
Phenotype ratio:

8. Problem #6 Cross a homozygous tall plant with a short plant.
Genotype ratio:
Phenotype ratio:

9. Problem #7
Cross a plant that is heterozygous for smooth pods with a plant that had constricted pods.
Genotype ratio:
Phenotype ratio:

10. Problem #8
When a tall plant is crossed with a short plant, some of the offspring are short. What are the genotypes of the parents and the offspring? What is the phenotypic ratio in the offspring?
Parent genotypes:
Offspring genotypes:
Phenotypic ratio:

11. Problem #9
Three-fourths (3/4) of the plants produced by a cross between two unknown pea plants have axial flowers and ¼ have terminal flowers. What are the genotypes of the parent plants?
Parent genotypes:

12. Problem #10
What cross would result in ½ of the offspring having green pods and ½ of the offspring having yellow pods?
Cross:

13. INTRODUCING….DRUM ROLL!!!
DIHYBRID CROSSES!!!

14. Try this one on your own!
In the deep rainforests of Brazil lives the Ocamazi tribe, amongst the members of this tribe exists a dominant trait for webbed feet (A), most have this trait, those that don’t have non-webbed feet (a). Additionally most members of this tribe webbed hands(B), a small minority have normal non-webbed fingers (b). Needless to say this tribe is great at swimming.
Problem: An Ocamazi princess Heterozygous for both webbed feet and fingers travels to another tribe to meet her soon to be husband, his tribe also has webbed feet which is also heterozygous for but no webbed hands which he is homozygous for. Draw the cross for the mating of these two people.

15. Solution Princess: FfWw Husband: Ffww Fw Fw fw fw Interpret this data!
F-Webbed Feet, f-Non Webbed Feet W- Webbed hands, w-Non Webbed hands

16. Challenge Problem Traits EE or Ee=Two eyes ee= One eye
You are a world-famous breeder of Purple-People Eaters.  Tragically, your entire stock perishes in a fire except for two individuals.  They are both heterozygous for all three traits desired.  The three traits are as follows:
Traits
EE or Ee=Two eyes        ee= One eye
HH or Hh= Two horns   hh= One horn
FF or Ff= Non-flying      ff= Flying