PEDIGREE

Question 1

Label key
How do we order:
-youngest/oldest
-males/females

Answer 1

Left : Oldest + Males
Right: Youngest + Females

Question 2

How do we draw pedigree trees? (1)

Answer 2

Question 3

How do we draw pedigree trees? (2)

Answer 3

Question 4

What is genetic relatedness?
How do we calculate genetic relatedness?

Answer 4

• Proportion of alleles that 2 individuals share due to recent common ancestors… excluding alleles shared simply by being of same species

> GR = 1/2 (n) per common ancestor
n= number of links (generational jumps) between the path that includes common ancestor

Question 5

What is important to note when it comes to monozygotic twins and GR?

Answer 5

• They share all their alleles so relatedness and one of their decendents cannot be directly calculate with this method.

Question 6

Calculate GR between Kirsty and Amelia?

Answer 6

Question 7

• If we skip generation the disease is likely…
• If we don’t skip a generation the disease is likely…

Answer 7

• Recessive
• Dominant

Question 8

What is reduced penetrance?

Answer 8

Genotype for the condition but NOT the phenotype there was an issue with the expression of genotype.

Question 9

1- If an affected child has unaffected parents what is the likely cause?

2- If an unaffected child has affected parents what is it likely?

3- Not sex-linked if…

Answer 9

1- Autosomal recessive

2- Dominant

3
- Condition caused by dominant allele:
- Father always passes on dominant allele on X chromosome to daughter, but she is unaffected.

• Condition caused by a recessive allele : father is unaffected but child is