2.5 Pedigrees

Question 1

What is a Pedigree?

Answer 1

A pedigree is a way of tracking the inheritance of a particular trait and determining the genotypes of individuals.

Question 2

How is Marriage Indicated?

Answer 2

It is indicated through a horizontal line connecting a circle and a square.

Question 3

How is Offspring Indicated?

Answer 3

It is indicated through vertical lines.

Question 4

What do shaded areas represent?

Answer 4

If an individual is shaded, it means they express the trait being studied.

Question 5

What are Autosomal Dominant Pedigree?

Answer 5

In an autosomal dominant Pedigree, only individuals with ‘EE’ or ‘Ee’ show the trait (shaded).

Question 6

What are Autosomal Recessive Pedigree?

Answer 6

In an autosomal recessive, only individuals with ‘ee’ show the trait (shaded).

Question 7

What are 2 Key Patterns of Autosomal Dominant Traits?

Answer 7

Key patterns:

• Affected children always have at least one affected parent.
• Two affected parents can have an unaffected child.

Question 8

What are 3 Key Patterns of Autosomal Recessive Traits?

Answer 8

Key Patterns:

• Parents don’t have to be affected, but both must be carriers.
• Two affected parents will only have affected children.
• The trait often skips generations.