1. Bellringer
Where are genes located (hint: chromosomal theory of inheritance)? What is genetic linkage?

2. Learning Target
Describe the purpose of a pedigree and use a pedigree to track a trait or disorder within a family.

3. Pedigrees

4. This is a Pedigree Chart showing colorblindness in a family
Why are more males than females colorblind?

5. A Pedigree Chart Is Like A Family Tree
A Pedigree Chart Is Like A Family Tree
A Pedigree Chart:
Shows genetic connections among individuals in a family.
Has Standardized symbols
May be used to estimate probability and patterns of inheritance over generations

6. Basic Symbols of A Pedigree

7. A Few Extra

8. Tracing the “Royal Disease” Hemophilia
Hemophilia is an X-linked recessive disorder characterized by the inability to properly form blood clots
Became known as the “Royal disease” because it spread to the royal families of Europe through the descendents of Queen Victoria
Became known as “curse of the Coburgs”

9. Queen Victoria’s Pedigree

10. What’s the likely MODE OF TRANSMISSION?
Autosomal Dominant
Autosomal Recessive
Sex-Linked Recessive  
Look for the “male pattern”, female carriers

11. What’s the likely MODE OF TRANSMISSION?
Autosomal Dominant
Autosomal Recessive
Sex-Linked Recessive 
In every generation, no carriers

12. What’s the likely MODE OF TRANSMISSION? 
Autosomal Dominant
Autosomal Recessive
Sex-Linked Recessive
Usually skips generations
But not always!*

13. Let’s build our own pedigree!
Debbie married David and had three children, Darren, Dawn, and Derek. David, Darren and Derek discovered they have muscular dystrophy. Derek married Didi and had two children, Denise and Destiny. Denise also has muscular dystrophy and married Dirk. They had two children, Dee and Deven. Dee has muscular dystrophy.
1) Draw the pedigree, showing the relationships between family members

14. Let’s build our own pedigree!
Debbie married David and had three children, Darren, Dawn, and Derek. David, Darren and Derek discovered they have muscular dystrophy. Derek married Didi and had two children, Denise and Destiny. Denise also has muscular dystrophy and married Dirk. They had two children, Dee and Deven. Dee has muscular dystrophy.
2) Identify the phenotype of each family member (affected, unaffected, carrier, etc.)

15. Let’s build our own pedigree!
Debbie married David and had three children, Darren, Dawn, and Derek. David, Darren and Derek discovered they have muscular dystrophy. Derek married Didi and had two children, Denise and Destiny. Denise also has muscular dystrophy and married Dirk. They had two children, Dee and Deven. Dee has muscular dystrophy.
3) Determine the genotype of each family member and the mode of transmission Mm mm mm Mm mm Mm mm Mm mm
Autosomal Dominant Mm mm