1. Pedigrees

2. For your notes: Copy the following
Draw I II 1 2 3 4 5
identifying

3. Pedigrees
Diagrams that display the occurrence of a genetic trait in a family through generations

4. How do I read a pedigree? 1. Circles represent females
2. Squares represent males
Horizontal lines represent marriages 1 2

5. How do I read a pedigree? Vertical lines represent children
A shaded circle or square means that individual has the trait
1=Mom, 2=Dad
3&5 =daughters
4 = affected son 1 2 5 3 4

6. How do I read a pedigree? Roman numerals indicate generations
I = grandparents
II = parents
III = children

7. Dominant Pedigree
At least one parent of an affected individual must exhibit the trait

8. Recessive pedigree
An individual that shows the trait may not have parents that show the trait
All children of affected parents will show the trait

9. Sex linked Pedigrees
Sex linked traits (x-linked) are more common in males
There are no direct male to male transmission because males transmit their Y chromosome to sons