Genetic Pedigrees

1. Genetic Pedigrees • Genetic pedigrees are like family trees • They show relationships, but also can track traits throughout a family • Squares = male; Circles = female • Shaded = has the trait (usually a disease) • Let’s create a simple pedigree…using PKU as an example • PKU is a recessive disease where sufferers lack a protein needed to properly digest foods. It can be fatal if untreated.

2. Creating a Pedigree Key H = Healthy h = PKU H h H h 1) Manny and Rosa are married and both are healthy. 2) They have 3 children. 3) Their oldest child, Jacob, has a recessive disorder called PKU. 4) Their middle child Erica and their youngest Matthew are healthy. • If healthy is dominant to PKU, fill in the missing genotypes. (start with what you know) hh H ? H ?

3. The Next Generation Key H = Healthy h = PKU 5) Erica meets Moe at college and the two become married. 6) Erica and Moe have 2 daughters. 7) Their youngest daughter Jamie shows signs of PKU while Amy does not. • Fill in the genotypes of the four individuals. (start with what you know) H h H h H ? hh

4. Pedigrees contd. • How that that example is finished, there is another family on the next slide. This family has a history of sickle cell disease in their family. • Try and fill in the genotypes of every person in this family.

5. Sickle cell anemia (recessive) pedigree Hint: 3 unknown hh hh hh Start with the shaded circles and squares. They must be hh because they have the disease. Key H = Healthy h = Sickle cell disease

6. Sickle cell anemia (recessive) pedigree Hint: 3 unknown H hh H hh H hh H H Everyone else is healthy so they have at least one capital H. hh H H H Key H = Healthy h = Sickle cell disease H

7. Sickle cell anemia (recessive) pedigree Hint: 3 unknown H h hh H hh H hh H H George must be Hh because he fathered Wilma and Tom. If he was HH, none of his kids would have the disease. hh H H H Key H = Healthy h = Sickle cell disease H

8. Sickle cell anemia (recessive) pedigree Hint: 3 unknown H h hh H hh H h hh H h H Sam and Ann must be Hh because Arlene is their mother. Arlene (hh) must pass h to each child she has. hh H H H Key H = Healthy h = Sickle cell disease H

9. Sickle cell anemia (recessive) pedigree Hint: 3 unknown H h hh H hh H h hh H h H h Michael must be Hh because Carla has the disease. If Michael was HH, then Carla would not have the disease. hh H H H Key H = Healthy h = Sickle cell disease H

10. Sickle cell anemia (recessive) pedigree Hint: 3 unknown H h hh H hh H h hh H h H h Daniel and Alan must be Hh because their father (Tom) passed h to each of them. hh H h H h H Key H = Healthy h = Sickle cell disease H

11. Sickle cell anemia (recessive) pedigree Hint: 3 unknown H h hh H ? hh H h hh H h H h Sandra, Tina, and Christopher are unknown. They are either HH or Hh. We cannot tell from this limited information. hh H h H h H ? Key H = Healthy h = Sickle cell disease H ?

12. Review • Which symbols show males? Females? • What does it mean if persons 1, 10, and 12 are colored black? • How are persons 1 and 8 related to each other? • Which two people are not genetically related to this family?