1. Following Traits in Families
Pedigrees
Following Traits in Families

2. Pedigree: A diagram that follows the traits through a family
Circles and Squares represent people
Shaded circles/squares represent people that have the trait “being followed”
A half-shaded symbol represents a ‘carrier’

3. Pedigree analysis
Pedigree analysis reveals Mendelian patterns in human inheritance
data mapped on a family tree
= male
= female
= male w/ trait
= female w/ trait

4. Simple pedigree analysis
What’s the likely inheritance pattern?
Simple pedigree analysis 1 2 3 4 5 6 1 2 3 4 5 6

5. Genetic counseling
Pedigree can help us understand the past & predict the future
Thousands of genetic disorders are inherited as simple recessive traits
from benign conditions to deadly diseases
albinism
cystic fibrosis
Tay sachs
sickle cell anemia
PKU

6. Douglas and Lauren have three children, two girls and a boy.
This line indicates a family
Douglas Lauren
Children are left to right, oldest to youngest

7. Douglas has brown hair. We will ‘follow’ this trait
Douglas has brown hair. We will ‘follow’ this trait. Show the brown hair trait by shading in the circle
Douglas Lauren

8. Lauren has blonde hair so we do not shade her in.
Douglas Lauren

9. Their oldest daughter and youngest son have brown hair also.
Douglas Lauren

10. Shade them in as well.
Douglas Lauren

11. You try: Ryan and Jessica have two children. Richard and Sarah.
Ryan does not have dimples, but Jessica does.
Richard has dimples but Sarah does not.
Jessica’s parents both have dimples
Jessica has a sister who does not have dimples
Follow the dimples trait

12. 1) Blue Eyes
Brandon is trying to figure out why he has blue eyes when his mother father and brother all have brown eyes.
Draw a pedigree for Brandon and his mother, father and brother.
Looking at family pictures he finds out that is father’s father had blue eyes.
Later he also finds out that his mother’s mother has blue eyes.
Follow the blue eyes trait

13. 2) Juan and Jamie have one daughter, Anna
2) Juan and Jamie have one daughter, Anna. All of them have hitchhiker’s thumb.
Anna marries a man named Adam with a straight thumb.
They have two sons the oldest has hitchhikers thumb the youngest does not.
Follow the hitchhiker’s thumb trait

14. 3) April and Anthony are brother and sister they both have brown hair, their parents both have brown hair
Their mother’s father has blonde hair
Their father’s mother has brown hair.
Their mother’s sister has blonde hair.
Their aunt got married and had two blonde haired children with a blonde haired man, one boy and one girl.
Follow the blonde hair trait

15. 4) Bob and Jane have 8 kids. Three daughters, then three sons, then 2 more daughters.
Bob is blood type A. Jane is blood type O. Child #1, 3, 7, 8 all have blood type A.
The oldest daughter gets married to a man with blood type O
They have 3 girls, all with blood type A.
Write the blood type genotypes for each of the individuals

16. Is the trait followed below: -Dominant. -Recessive. -Sex-Linked
Is the trait followed below: -Dominant? -Recessive? -Sex-Linked? Explain how you know!