What kind of information could a family tree like the one shown tell you?

What do the branches on the tree represent?

What kind of information might one be able to get from a family tree?

This family tree is easier to read and shows more information.

Parents

Children

Marriage

What else could you learn from a family tree?

Squares are always males, and circles are always females.

Lines between males and females designate marriage.Connected lines to marriage lines indicate children.

Shapes colored mean inheritance of trait.

Pedigrees are maps of families used to determine how traits are passed down through generations of the family.

What information can we learn from this pedigree?

Male

Female

4 Generations

Trait Inherited

Let’s work together to see how to interpret a pedigree. We will complete the Pedigree worksheet on Colorblindness.

4

21

35

6

KEY

Normal female

Affected female

Normal male

Affected male

Genotypes:

1. ____ 2. _____ 3. _____ 4. _____ 5. ____

6. ____

Huntington’s Disease (H,h)

Dominant Trait

4

21

3

5

Genotypes:

1. ____ 2. _____ 3. _____ 4. _____ 5. ____

KEY

Normal female

Affected female

Carrier female

Normal male

Affected male

Sex-linked Trait

1. How many generations are shown?

2. How many children did couple A-B have?

3. What is the relationship between K and G?

4. What must be the genotype for H?

5. What is the genotypes for E and F?

6. What are phenotypes for SS, Ss, and ss?

7. How many people have sickle cell?

S=normal

s=sickle cell