Lecture 1

Question 0

Examples of autosomal recessive disorders

Answer 0

Cystic fibrosis, sickle cell anemia

Question 1

Examples of Autosomal Dominant disorders

Answer 1

Marfan, brca 1 and 2, familial hypercholesterolemia

Question 2

Examples of x linked disorders

Answer 2

Duchenne muscular dystrophy, hemophilia, color blindness

Question 3

How would you find genetic components of common disease?

Answer 3

Family studies, twin studies, adoption studies

Question 4

Recurrence risks for common diseases (threshold traits)

Answer 4

• Degree of relatedness
• Number of affected family members
• Sex of affected relatives
• Degree of severity in affected individuals

Question 5

Linkage disequilibrium (LD)

Answer 5

Two genes are close enough to one another that crossing over rarely or never occurs between them so they are consistently inherited together

Question 6

What are strategies for genetic studies of complex diseases?

Answer 6

Linkage studies
-study affected and unaffected individuals and look for areas that are common only in affected individuals

Association studies 
-take unrelated cases and unrelated controls, genotype them, look for differences
   -positional candidate: all genes     
    present under a linkage curve
   -biological candidate: chosen if a
    metabolic pathway for a disease is 
    known and genes within that 
    pathway are known

Sequencing

• targeted sequencing
• whole genome
• exome sequencing

Question 7

What are missing heritability models?

Answer 7

• Infinitesimal model - many common variants of small effect
• rare variant model - many rare alleles of large effect
• broad sense heritability - epistatic interactions, genotype and environment interactions, epigenetics
• common disease common variant model (wrong)

Question 8

Odds ratios

Answer 8

OR=1 - no effect (baseline)

OR>1 - odds of developing disease are X times higher (risk factor)

OR<1 -odds of developing disease are x times lower (protective factor)

Question 9

Bonferri Correction

Answer 9

Adjust the p value by the number of tests being done (important for GWAS)