1. Mrs Stewart
Honors Biology
Pedigree Charts

2. What is a pedigree?

3. Pedigree Charts Why do we use them?
Then what information do we use to determine inheritance of traits?
Record ancestry and/or trace the geneology of a trait through the family lines
Genetic Testing
Medical History
Historical Data
Family Records

4. Symbols

5. Pedigree Charts - Symbols

6. Pedigree Chart - Symbols

7. Pedigrees

8. Example: Hemophilia in the royal family

9. How is Hemophilia inherited?
Sex-Linked Recessive Disorder

10. Example: Hemophilia in the royal family
What are some clues that you can see in this pedigree that could tell you this is a sex-linked disorder?

11. Pedigrees
Albinism
Polydactyly

12. Pedigree Chart

13. How do we read a Pedigree?
Which family members are Albino?
How is Ann related to Pam?
Bill
Sam
Pam is Ann’s Grandmother

14. What are Inheritance Patterns?
Inheritance Pattern: The transmission of genetically encoded traits/conditions/diseases to offspring
In other words: How the gene is transmitted/passed on.

15. What are the different ways a genetic condition can be inherited?

16. Autosomal Recessive Skips generations Affects males/females equally
Pedigree may show carriers

17. Autosomal Dominant
There will not be carriers – those with the gene will be “affected”
Will probably not skip generations
Will affect males/females equally

18. Sex-Linked Recessive More males affected than females
Skips generations

19. What is the inheritance pattern for this disorder?

20. Autosomal Recessive How do we know? “affected” skips generations
carriers

21. Enrichment Assignment
Create a family pedigree for the following trait:
Ability to taste “bitter”
Mrs. Stewart has strips of paper called PTC paper that will determine this ability.

22. PTC The ability to taste PTC (bitter) is inherited.
BB = strong bitter taster
Bb = somewhat able to taste bitter
bb = cannot taste bitter

23. How to complete the enrichment assignment:
15 possible enrichment points
Have each family member (immediate household family) taste the PTC paper.
Use their responses to identify their genotypes
Create a pedigree that shows the trait throughout your family
10 points extra if you include pictures of each family member while tasting the PTC paper.