Lecture 2 - Inheritance and Pedigree Analysis

Question 1

5 classes of human genetic disorders:

Answer 1

1. Single gene
2. Chromosomal
3. Multifactorial
4. Mitochondrial
5. Diseases of unknown etiology

Question 2

Which class of inheritance manifests as 50% of male children affected, and 50% of female children are carriers.

Answer 2

X-linked recessive inheritance

Question 3

What class of inheritance is is Hemophilia A?

Answer 3

X-linked recessive; caused by deficiency of the clotting factor VIII

Question 4

Which mode of inheritance leads to expression of a disease or trait in both hemizygous males and heterozygous females?

Answer 4

X-linked dominant inheritance

Question 5

What class of inheritance is leber hereditary optic neuropathy?

Answer 5

Mitochondrial inheritance; due to complex I genes in mitochondrial DNA

Question 6

What is the term for the first case diagnosed in the family?

Answer 6

Proband

Question 7

An individual harbors a genotype but fails to express the phenotype. What is the term for this?

Answer 7

Variable penetrance

Question 8

Duchenne Muscular Dystrophy is an example of what kind of defect?

Answer 8

Defect of structural protein

Question 9

Cystic fibrosis is an example of what kind of defect?

Answer 9

Transport defect

Question 10

Familial hypercholesterolemia is an example of what kind of defect?

Answer 10

Receptor protein defect

Question 11

What are Mendel’s two laws?

Answer 11

1. Law of Segregation

2. Law of Independent assortment

Question 12

Which law says that genes for different traits assort independently of one another in the formation of gametes? When is this true?

Answer 12

Law of Independent Assortment - applies if traits are in different chromosomes and traits are independent

Question 13

What class of genetic disease is due to substrate accumulation, product deficiency, or both?

Answer 13

Enzyme defect

Question 14

Which types of diseases tend to run vertically?

Answer 14

Dominant diseases