1. Mrs. Stewart
Biology
Pedigree Charts

2. Objectives Can create a pedigree using family history information
Can analyze a pedigree for genotypes
Can predict inheritance for a genetic trait/disorder

3. What is a pedigree?
Pedigrees are a “family tree” that is used to show the inheritance of genetic traits/disorders

4. 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

5. Symbols

6. Pedigree Charts - Symbols

7. Pedigree Chart - Symbols

8. Symbols Check: Is person I-2 male or female?
How are II-1 and II-3 related?
List two people who are a couple.
Who is the grandmother of person III-1?

9. Create a pedigree Using the family history below, create a pedigree:
Anne and Max are brother and sister. Anne is 35 and Max is 33. Their parents are Kate and Joe.
Anne is married to Curtis, and they have 3 kids: Devon (f), Ken (m) and Kimberly (f).
Max is married to Natalie and they have 2 kids: Ryan (m) and Donna (f).
Max, Curtis and Donna all have cystic fibrosis.

10. Pedigree Check

11. How do we read a Pedigree?
Which family members are Albino?
How is albinism inherited?
Bill
Sam
Dominant or recessive? Autosomal or sex-linked?

12. Pedigrees

13. 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.

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

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

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

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

18. Example: Hemophilia in the royal family

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

20. 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?

21. Pedigrees
Albinism
Polydactyly

22. Pedigree Chart

23. What is the inheritance pattern for this disorder?

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

25. Pedigree Practice: How is the trait inherited?
What is the genotype of person II-3?
Should persons II-1 and II-2 get checked to see if they are carriers?
Autosomal Recessive
Carrier - heterozygous
Yes

26. Pedigree Practice: How is the trait inherited?
What is the genotype of person II-3?
Are there carriers for this trait?
Autosomal Dominant
Homozygous recessive No

27. Assignment:
Complete pedigree worksheet packet