Genetic Pedigrees

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 certain foods. It can be fatal if untreated. Genetic Pedigrees

Creating a Pedigree H h H h hh H ? H ? Key H = Healthy h = PKU H h H h hh 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)

The Next Generation Key H = Healthy h = PKU H h H h H ? hh 5) Erica meets healthy 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)

Pedigrees contd. Now 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.

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

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

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

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

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

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

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 ?

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? List the genotypes for as many people as possible. (H = healthy; h = disease)