Pedigrees

Question 1

What is mating between family members called?

Answer 1

Consanguineous

Question 2

What are some characteristics of autosomal dominant disorders?

Answer 2

• sexes equally effected
• all forms of transmission are present
• affected individual always has an affected parent

Question 3

What are some characteristics of autosomal recessive disorders?

Answer 3

• sexes equally affected
• allele can skip generations
• all forms of transmission are present

Question 4

What are some characteristics of X-linked dominant disorders?

Answer 4

• If the father is affected, he will always pass the affected allele onto his daughter
• fathers cannot pass the trait to their sons
• an affected individual always has an affected parent

Question 5

What are some characteristics of X-linked recessive disorders?

Answer 5

• affected males will always express the disorder as there ins no compensatory second X chromosome
• fathers cannot pass X-linked traits to their sons
• allele can skip generations

Question 6

What is an example of an autosomal dominant disorder?

Answer 6

Huntingtons disease

Question 7

What is an example of an autosomal recessive disorder?

Answer 7

PKU, Cystic Fibrosis, Sickle cell anaemia

Question 8

What is an example of an X-linked dominant disorder?

Answer 8

Rett syndrome, fragile x Syndrome

Question 9

What is an example of an X-linked recessive disorder?

Answer 9

Red-green colour blindness, Haemophilia A

Question 10

What are some reasons for X-linked recessive disorders?

Answer 10

• excess of males affected
• no father to son transmission
• affected female with a similarly affected father