Multifactorial Inheritance Flashcards
1
Q
Types of non-Mendelian inheritance
A
- Polygenic
- Multifactorial (or common complex)
- Maternal mitochondrial
2
Q
How are genetic and environmental influences for multifactorial inheritance identified?
A
Observational studies of the incidence of diseases in different groups of people
3
Q
How is evidence gathered for observational studies?
A
- Familial clustering
- Twin studies
- Adoption studies
- Population and migration studies
4
Q
What is empiric risk?
A
Chance that a disease will occur in a family, based on experience with the diagnosis, past history and medical records rather than theory
5
Q
What is the threshold model of multifactorial inheritance?
A
- Bell-shaped curve with liability on x-axis and number of affected people on y-axis
- Liability caused by combination of genetic and environmental factors
- Threshold level is the point on the x-axis where the people above it have the disease
6
Q
How are the genetic components of common complex disorders identified?
A
Genome-wide association studies (GWAS)
7
Q
How does a genome-wide association study work?
A
- Take thousands of people knowing who does and doesn’t have the disease
- Test up to 500,000 SNPs in each person by microarray analysis
- Identify genetic alterations associated with disease
8
Q
By how much are risks usually increased by specific SNP genotypes?
A
1.1x - 1.5x
