Pedigrees

Question 1

What is a pedigree chart?

Answer 1

a diagram showing the expression of a trait over multiple generations

Question 2

What are the important conventions of pedigree charts?

Answer 2

horizontal lines represent mating between two individuals
vertical lines represent the link between two generations
circles are females
squares are males
coloured shapes are affected individuals

Question 3

What is the autosomal dominant inheritance pattern?

Answer 3

1. If both parents are affected, the offspring may be unaffected
2. If neither parent is affected, then the offspring will not be affected
3. If an offspring is affected, there must be an affected parent
4. Rarely skips a generation

Question 4

What is the autosomal recessive inheritance pattern?

Answer 4

If both parents are affected, the offspring must be affected
2. If neither parent is affected, the offspring may be unaffected
3. If an offspring is affected, there may be an affected parent
4. The trait can skip generations