Module 7 Flashcards
Genetics of Obesity
List the 6 causes of monogenetic obesity.
- Leptin deficiency – ob/ob mouse
- Leptin receptor deficiency – db/db mouse
- Prohormone convertase (PC1) defect
- Melanocortin – 4-receptor (MC4R) defect
- POMC deficiency
- PPAR-γ defect
What is the most common cause of monogenetic obesity?
Melanocortin-4-receptor (MC4R) defect
How is the FTO gene locus SNP linked with obesity?
- May modulate feeding through leptin/STAT3 signalling pathway
- May impact processes of browning of WAT
- May affect adipogenesis
- Highly expressed in hypothalamus
Explain how Genetic Investigation of Anthropometric Traits (GIANT) studies work.
- Hypothesis-free analysis of genome variation
- Uses genetic database
- Looks for highly-replicable associations using a very high statistical significance threshold
What was the finding of the GIANT study?
BMI loci genes were found in in neuronal genes (especially those associated with appetite)
List the 3 ways that modifications are made in epigenetics.
- Methylation/demethylation ⇒ usually supresses expression
- Histone modification ⇒ compactness of DNA wound around histones impacts expression
- Non-coding RNA (micro-RNA)
What is meant by the expression, “genetics loads the gun, our environment pulls the trigger” in relation to obesity?
Our genetics predisposes us to risk for obesity, however it is our environment that makes it possible for the disease to thrive.