1. Inheritance of Traits Probability Carriers Autosomal Sex-linked
Pedigrees
Complex patterns of heredity
Incomplete dominance
Codominance
Multiple Alleles
Practice

2. Inheritance of Traits
Probability- the likelihood that a specific event will occur
When you flip a coin, there is a 50/50 chance it will land tails side up
If there are 4 kids in a family, probability says 2 will be girls and the other 2 will be boys

3. Inheritance of Traits
Carrier- an individual who is heterozygous for an inherited disorder but does not show symptoms.
Ex. Linda is a carrier for albinism.
Genotype-(Aa)
Phenotype- not albino
Even though she does not display the symptoms, she can still pass on albinism to her children.

4. Inheritance of Traits
Autosomal- when a gene is autosomal, it will appear in both sexes
Sex-linked- when a gene is sex-linked, it is found only on the X or Y chromosomes so the effects are only seen in males.
Remember, males are (Xy) and females are (XX)
Examples- colorblindness, hemophilia, Cystic Fibrosis and Sickle Cell Anemia

5. Inheritance of Traits Sex-linked Punnett Square for colorblindness: X
Key:
XX- female
Xy- male
Xby- colorblind male
XXb- female carrier
XbXb- colorblind female Xb y
What are the offspring?

6. Inheritance of Traits Sex-linked Punnett Square for colorblindness: Xb
Key:
XX- female
Xy- male
Xby- colorblind male
XXb- female carrier
XbXb- colorblind female X y
What are the offspring?

7. Inheritance of Traits Sex-linked Punnett Square for colorblindness: Xb
Key:
XX- female
Xy- male
Xby- colorblind male
XXb- female carrier
XbXb- colorblind female Xb y
What are the offspring?

8. Pedigrees
Pedigree- a family history that shows how a trait is inherited over several generations
Useful to track the carriers of genetic disorders in families
Can be used for both autosomal and sex-linked disorders

9. Pedigrees Pedigree for albinism: Key: Female Male (P1) Female carrier
Female with albinism
Male with albinism
Married
with children
(P1)
(F1)
(F2)
*The order of children is from left to right

10. Pedigrees Pedigree for albinism:C D E F G H I J K
Which individuals are heterozygous for albinism?
Which are homozygous for albinism?
Which individuals have albinism?
Which generations have an individual with albinism?

11. Complex Patterns of Heredity
Polygenic inheritance- when several genes influence a characteristic
Incomplete dominance
Codominance
Multiple alleles

12. Complex Patterns of Heredity
Incomplete dominance- when an individual displays an intermediate/middle phenotype of the parents
Ex. A red (RR) snapdragon flower is crossed with a white (rr) one and their offspring are pink (Rr)

13. Complex Patterns of Heredity
Codominance- when two dominant alleles are expressed at the same time
Ex. Blood types- AB blood A A B AB AB AB AB B

14. Complex Patterns of Heredity
Codominance
Ex. Roan horses (have both red and white hair)

15. Complex Patterns of Heredity
Multiple alleles- genes with 3 or more possible alleles
Ex. Blood types- A, B, O (AB- codominant)

16. Practice Blood Type
If a man is homozygous for type B blood, and has a child with a homozygous woman with type A blood, what are the possible blood types of the child?
Phenotype
Genotype
Type A
Type B
Type AB
Type O
AA or AO
BB or BO AB OO

17. Practice Blood type
A man is heterozygous for type A blood and has a child with a woman that has AB blood. What are the possible blood types of the child?
Phenotype
Genotype
Type A
Type B
Type AB
Type O
AA or AO
BB or BO AB OO

18. Practice Incomplete dominance
Assume:
Red= RR
White = rr or WW or R’R’
Pink= Rr or RW or RR’
You cross a red flower with a white flower:
What happens?