Nutrition and Ageing L9-10 Flashcards
Chronic diseases are multifactorial.
Name the 5 factors involved.
- Nutrition
- Genetic factors
- Lifestyle factors (smoking, exercising, drinking, etc..)
- Age
- Molecular and cellular damage / metabolic pathways
Ageing = _______
Accumulation of damage
Define SNP (Single Nucleotide Polymorphism).
A Single Nucleotide Polymorphism is a DNA sequence variation occurring commonly within a population (e.g. 1%) in which a single nucleotide — A, T, C or G — in the genome differs between members of a biological species or paired chromosomes.
Coding SNPs:
_____1_____ (no change in AA, genetic code degeneration)
_____2_____ (missense : change in AA /nonsense: premature STOP codon)
- Synonymous
2. Nonsynonymous
Most ______ have no functional effects. Some ______ affects key regulatory regions.
SNPs
SNPs may fall within what 3 sequences/regions?
- Coding sequences
- Noncoding sequences
- Intergenic regions
What is the aim of the International HapMap Project.
Identification and catalog of common genetic variants that occur in human beings.
What 2 approaches are used to find SNP associated with a disease?
- Candidate SNP approach
- Hypothesis-free approach
Describe the pros and cons of Candidate SNP approach.
Pros
- Can take into account biomarkers of nutritional status (vit. conc, etc)
- Can take into account genetic interactions between SNPs (SNP combination)
Cons
- Biased: based on prior knowledge and selection of SNP of interest
- Typically 1-10 SNPs
Limited by characteristics of study population (100s-1000)
What studies is the Candidate SNP approach used for?
- Small number candidate SNPs
- SNPs in one metabolic pathway
What studies is the Hypothesis-free approach
used for?
- Genome-Wide Association Studies (GWAS)
______: naturally occurring form of folic acid (Vit B9) in the body.
Folate
Folates are important for what 5 points?
- DNA synthesis: purine/pyrimidine synthesis
- DNA repair
- Donors of methyl group in the Folate “1 Carbon” metabolism
- Key to methylation reactions
- DNA methylation (silencing of genes, cancer…)
- Lipid and protein methylation
- During pregnancy (supplementation, 400mg= 2*RNI)
- Neural tube formation in early stage of development
- Cell production, DNA/ RNA synthesis
Selenoprotein P (SePP):
Major ___1___ selenoprotein (60% ___1___ Se) and best biomarker of active Se.
Synthesized in the ___2___ from dietary Se.
Secreted in the ___1___, transports hepatic Se to other organs for synthesis of other selenoproteins.
2 ___1___ isoforms: 60kDa (10sec) and _3_kDa.
- Plasma
- Liver
- 50
Define a Genome-wide association study (GWAS).
A study in which several hundred thousands to more than a million common genetic variations (SNPs), theoretically covering the entire human genome, are simultaneously tested for association with a observable trait/complex genetic disease in thousands of individuals (cases and controls).
Ageing rate (accumulation of damage) is a balance between what? (2)
- Cellular damage
- Repair and protection mechanisms
Define monogenic disease.
A disease which is the result of a single defective gene.
Inherited according to Mendelian genetics.
Define multifactorial disease.
A disease caused by the effects of multiple genes in combination with lifestyle and environmental factors.
Name a non-modifiable risk factor in multifactorial disease.
Genetics.
Name 4 modifiable risk factors in multifactorial disease.
- Diet
- Exercise
- Alcohol consumption
- Age
Give examples of multifactorial diseases. (4)
- Heart disease
- Cancer
- Dementia
- Diabetes
______ diseases are multifactorial.
Chronic
When can a mutation become an SNP. (2)
- When the mutation is a single base change
- When the mutation becomes stable with a population (>1% of population)