1. 4.3.12 Human Pedigrees Drawing and Analysis

2. Genetic Counseling Helping individuals and prospective parents Your learning gives you the opportunity to determine some probabilities and patterns of inheritance yourself!

3. Determining Risk Probability of inheriting a particular gene is dependent on parents’ genes. Sometimes information about a parent is not enough or unknown. We use genetic information about other family members to help “solve the puzzle” as best as possible

4. Pedigrees A pedigree is a biological family tree that shows the interrelationships between parents and children across generations. Helps illustrate a pattern of inheritance for a single trait through that family

5. Pedigrees

6. Standard Symbols in Pedigrees MaleUnspecified Gender Female

7. Standard Symbols in Pedigrees Clinically Unaffected Clinically Affected Carrier Not Clinically Affected

8. Standard Symbols in Pedigrees DeceasedStill Birth / miscarriage SB #wk

9. Conventions in Drawing Pedigrees Male partner on left (usually) Parents Regardless of Social Relationship

10. Conventions in Drawing Pedigrees Full Siblings (in order of age from left to right) I II 1 2 123

11. Conventions in Drawing Pedigrees Dizygotic Twins Monozygotic Twins I II 1 2 123 4

12. Conventions in Drawing Pedigrees Adopted Blood Relative Separated I II 1 2 3 123

13. Patterns of Inheritance Dominant: –Trait is expressed in every generation eg. Huntington’s, brown eyes –Not seen in offspring unless present in a parent Recessive: –Trait may skip generations eg. TaySachs Sex-Linked: –Y linked – only males are clinically affected –X linked – affected males may have normal parents, affected females must have affected father

14. Simple Pedigrees Pg. 138 DBQ Pg 140 DBQ Pg 145 DBQ

15. Determining Risk Ms. Soule would like to know what risk she has of developing these conditions. Several individuals in Ms. Soule’s family have been diagnosed with either Breast Cancer (BRCA) or Polycystic kidney (PKD). PKD vs. healthy kidney

16. b) Ms Soule’s Pedigree – Matrilineal/Genetic (1) I have a daughter. I have one sister and she has a son and a daughter. My mother has a sister and a brother. My mother’s sister has two daughters. My mother’s brother has a son and a daughter. My maternal grandmother was second youngest of sisters. (2) The oldest of my maternal grandmother’s sisters had four daughters. The eldest of these had two daughters of her own and she also developed breast cancer. (3) The next of my grandmother’s sisters had one daughter. Her daughter and husband both died from polycystic kidney disease. (4) The youngest of my grandmother’s sisters had two sons. One of those sons had one daughter; the other had one son and a daughter. (5) My grandmother’s mother had a sister. My grandmother’s maternal grandmother died of breast cancer. My maternal grandmother’s mother had breast cancer and so did my grandmother. Two of my grandmother’s sisters had breast cancer (not the one whose family showed polycystic kidney disease). 1)Which disease should Ms Soule be more worried about PKD or breast CA? 2)Breast CA has not been seen in Ms Soule’s family in her generation or her parent’s generation. Does that mean she is not at risk? What kind of inheritance is this?

17. Pedigree Problems a) Ms Soule’s Pedigree – Social I am married to Peter. I have one sister, Lindsay. She is married to Joe and has a (cute!) son, Jeremy. My parents (Doug and Judy) are both alive and still married. My dad is an only child, but my mom has a brother, Pete, and a sister, Becky. 1) Becky was married to Jeff and had two daughters (Amy and Addy) and one miscarriage. 2) They divorced and both remarried. 3) Jeff’s new wife had a son from a previous marriage and together they had a second son. Becky and her new husband did not have any kids. My uncle Pete married Chris and had a son, Mark, and a daughter, Stephanie. Stephanie is married with two daughters and a son of her own. Pete and Chris divorced, and Pete remarried Barbara, who has one son from a previous marriage. Her son is married and has a son and daughter. My mom’s parents are still alive and married. 4) My dad’s parents divorced, and his mom remarried Joseph who had two children from a previous marriage, but I don’t know if they’re boys or girls. 5) My father’s father passed away.