Week 3 : Genetics and Population Health Flashcards
What is deoxyribonucleic acid (DNA) made up of?
- A deoxyribose sugar
- A base
List the 4 possible bases.
Adenine - A
Thymine - T
Cytosine - C
Guanine - G
What is Mendelian Inheritance?
Refers to certain patterns of how traits are passed from parents to offspring (one gene + environment)
What is Complex Inheritance?
Traits that have a genetic component that does not follow strict Mendelian inheritance and may involve the interaction of two or more genes or gene-environment interactions.
What is a genetic predisposition?
An increased likelihood of developing a particular
disease based on a person’s genetic makeup.
List 2 ways we can detect genetic variants.
- DNA Microarray
- Genetic Sequencing
How does DNA Microarraying work?
Sample DNA from blood or saliva is extracted, cut into fragments and analysed on a DNA-microarray chip.
What is read depth?
The number of times the genome is read during sequencing.
Why are candidate-gene studies not usually successful?
- Small sample sizes
- Inadequate or loose statistical thresholds
- Inefficient number of genetic markers tested
What does GWAS mean?
Genome-wide association studies
What is the GWAS pipeline?
Large patient sample > Simultaneous genotyping > Statistical analysis
How many SNPs are tested during GWAS?
All SNPs
What is the issue with GWAS?
Restricting to Europeans limits the generalisability of
findings and may miss genes poorly captured by
European genetic variation.
How can genetic data be used in criminal investigations?
- Racial profiling
- Matching DNA from the crime scene
What is a polygenic risk score (PRS)?
It’s a score used to estimate an individuals genetic risk/liability for a certain disease or trait.
How is PRS calculated?
Based on GWAS results.
What is PRS used for?
- Identify shared etiology between phenotypes
- Evaluate clinical utility of genetic data for complex disease
- Stratification of samples.
- Comparing outcome between patients with low/high risk
- Utilise powerful summary statistics from large studies to inform genetic risk profiles in small
samples
Why is knowing underlying genetic risks important?
- Prediction of health
- Personalised treatment
- Improve diagnosis, select optimal treatment, preventative medicine.
- Another piece of the info to add to other data to help decision making in healthcare
What does having a polygenic score in the 95th percentile mean?
You do not have a 95% risk of developing the disease, but out of 100 people your
background risk is higher than 95 others.
