1. Pattern of Inheritance (POI) 2
Genetics
Punnett’s Square
Pattern of Inheritance (POI) 2
Incomplete Dominance

2. POI: Incomplete Dominance
The first type of Punnett’s Square Problem we are going to learn about is called Incomplete Dominance.
The rules for this POI are:
Both alleles are dominant
When heterozygous (mixed), the alleles show a blending of both variations in the phenotype.
Essential Vocabulary for this section:
Hybrid – Heterozygous individual
Snap Dragon – type of flower know to exhibit Incomplete Dominance.

3. Four O'clock flowers on board
Page 15 of packet

4. This is an example of incomplete dominance
This is an example of incomplete dominance. One parents has the RR genotype for red petals and the other parent has the WW genotype for white. Neither phenotype is fully dominant over the other phenotype. This is why it is said to be incomplete dominance. Therefore, the phenotypes red & white together make a pink phenotype RW.

5. Practice Problem #1

6. Pattern of Inheritance (POI) 3
Genetics
Beaver + Duck
= Platypus
Punnett’s Square
Pattern of Inheritance (POI) 3
Co-dominance

7. POI: Co-Dominance
The second type of Punnett’s Square Problem we are going to learn about is called Co-Dominance.
The rules for this POI are:
Both alleles are dominant
When heterozygous (mixed), the alleles show both variations in the phenotype.
Essential Vocabulary for this section:
Hybrid – Heterozygous individual
Roan – Hybrid of Red and White fur variations
Erminette – Hybrid of Black and White feather variations

8. So if the flowers from the last example demonstrated co-dominance, what would we see?

9. Genotype: RW

10. Chicken example on pro

11. This is an example of Co-dominance
This is an example of Co-dominance. One parent has the phenotype black and the other parent has the phenotype white. Both of the phenotypes are dominant so, consequently they are BOTH shown as a third phenotype black + white being expressed. The offspring has a genotype of BW…

12. Genetics Punnett’s Square Pattern of Inheritance (POI) 4
Sex-Linked (X-Linked)

13. POI: X-linked Inheritance
The second type of Punnett’s Square Problem we are going to learn about is called Sex-linked Inheritance.
The rules for this POI are:
Traits are attached to sex chromosomes. Specifically the X- chromosome.
Outside of the attachment to the X- Chromosome these problems fall under the POI of Simple Dominance.
Essential Vocabulary for this section:
Hybrid – Heterozygous individual
Red/Green Colorblindness – inability to see differences between red and green
Hemophilia – inability to stop bleeding.
Carrier – Individual that has a recessive allele but does not have the disease

14. Pattern of Inheritance (POI) 5
Genetics
Punnett’s Square
Pattern of Inheritance (POI) 5
Multiple Alleles

15. POI: Multiple Alleles The rules for this POI are:
This POI uses the rules of Simple Dominance and Co- dominance.
This POI is very complex, it is a combination of two separate POI.
This POI has 3 alleles.
Essential Vocabulary for this section:
Blood Typing – proteins covering blood cells have specific shapes and properties.

16. Practice Problem #1
A man with homozygous type B marries a woman with type O blood.

17. Practice Problem #2
A man with type AB blood marries a woman with heterozygous type A blood.

18. Practice Problem #3
A man with homozygous type A blood marries a woman with heterozygous type B blood.