1. Pedigrees

2. What is a pedigree? A family tree that shows the passage of a trait

3. Following Traits in a Pedigree Steps: 1.Fill in all recessive individuals 2.Determine unknowns

4. An Example The trait we are tracking is dominant. Determine the genotype of individuals 1, 3, 6, 7

5. This pedigree is for lung disease. The trait is recessive What is the genotype for individuals 2, 4, 10, 12 and 13 12 98 7 65 43 13 12 1110 141516

6. DETERMINING MODE OF INHERITANCE ON A PEDIGREE

7. Modes of Inheritance Autosomal Recessive Autosomal Dominant Sex-linked recessive Sex-linked dominant

8. Autosomal Dominant vs. Recessive Things to look for –Autosomal Recessive traits Occur less often Skip generations Two parents with the trait MUST give the trait to their kids –Autosomal Dominant Traits Occurs more often

9. How can we figure it out Look for sections of the family that the parents either both –have the trait –do not have trait First assume the trait dominant (assume all dominant people are heterozygous) and see if it possible Then assume it is recessive (assume all dominant people are heterozygous) and see if it possible

10. For each of the following determine if it can be a recessive trait and/or a dominant trait

11. Sometimes____________

12. A bigger one 1.Is it autosomal recessive or autosomal dominant? How do you know? 2.Write the genotypes of the people you know

13. Another bigger one 1.Is it autosomal recessive or autosomal dominant? How do you know? 2.Write the genotypes of the people you know

14. What if you cannot find parents that either don’t have it or do have it. Cry! Traits that occur less often are usually recessive Traits that skip generations are usually recessive To be sure you have to go through the entire pedigree and assume each possibility

15. FOR EXAMPLE

16. Another Example

17. Recessive Sex-Linked More men will be affected an affected female will transmit the trait to all male children In order to have an affected female the dad must have the trait

18. Can these pedigrees be recessive sex-linked?

19. Other Types of Inheritance Sex-linked dominant If Dad has the trait, all the daughters must have the trait Y linked: If Dad has the trait, all the sons must have the trait Mitochondrian Genes An affected mother will give the trait to all children