Nutritional Genomics - Bemis Flashcards

1
Q

What are the three sub-disciplines of nutritional genomics?

A
  1. Nutrigenetics
  2. Nutrigenomics
  3. Nutritional epigenetics
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2
Q

What does nutritional genomics mean?

A
  • Gene – environment interactions that may be managed to prevent diet related disease
    • e.g. gene-environment interactions in the Cytochrome P450 family and specific therapeutics
  • Understanding single gene function and the direct relationship to nutrients and the larger impact on disease
  • This is becoming a new medical discipline.
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3
Q

What is nutrigenetics?

A
  • Refers to functional changes in the nucleic acid code that influences a persons response to nutrients
    • genetice: individual SNP
  • Variation in genes occurs over evolutionary time and results in gene variants that may make a gene more functional or less
  • Variation may be associated with geographic ancestry
  • A gene variant may allow the better use of a specific nutrient by the organism
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4
Q

What is the goal in nutrigenetic studies?

A

Seek to identify functional outcome of a change in the nucleic acid code (variant) usually a SNP that results in a change in the response to a nutrient

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5
Q

What are variants?

A
  • Variants are also called alleles
  • The majority of variants are at a single DNA base
  • When the variant occurs in a population it is called a single nucleotide polymorphisms (SNPs)
  • Technically all SNPs or variants are mutations but mutation is usually reserved for a genetic change with deleterious consequences.
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6
Q

What are some examples of Nutrigenetics?

A
  • Paul’s genotype is an example of nutrigenetics C282Y mutation in HFE gene contributes to hemochromatosis
  • Lactose intolerance is the norm in adulthood but due to a SNP in the LCT gene many Caucasians of northern European descent are able to keep making lactase and breaking down lactose
  • Celiac disease is genetically determined but environmentally triggered
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7
Q

What are the potential benefits of Nutrigenetics?

A
  • The benefit to patients is that it would be possible to know in advance that a person is at risk of a potentially fatal anaphylaxis
    • or that the physician may tailor treatment to the individuals metabolic capability
  • May help the physician to confirm suspected dietary conditions, such as lactose intolerance, Celiac disease, Hemochromatosis
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8
Q

What tools are used to discover new gene – environmental interactions? How are the genes of interest discovered?

A
  • Deep sequencing
    • study the mechanism of how genes and environment interact
  • GWAS a genome-wide association study
    • study of many different individuals to see if any variant is associated with a trait
    • By function, regulation, co-expression, location in the genome
    • LARGE amount of data for numerous people
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9
Q

What does Necessary and Sufficient mean in terms of a SNP found through Nutrigenetics?

A
  • Biochemical and Physiological confirmation that the SNP is required (necessary) by itself (sufficient) to cause the change in phenotype
  • If a SNP (or variant) is necessary (required) but not sufficient it would mean that it is always present but is not the only requirement for the condition.
  • Sufficient means that the SNP (or variant) is the actual cause of the condition,
    • could also be assisted by other SNPs in the same gene or in another location, which might modulate its behavior in a positive or negative manner.
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10
Q

What is Nutritional Genomics?

A

environmental factors that effect gene expression (may be multiple genes)

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11
Q

What is the goal of Nutrigenomics?

A
  • Seeks to identify environmental factors that effect gene expression (global gene expression/or single gene variants)
  • The goal is to use food in a targeted fashion rather than just use food to supply the raw materials for cellular function.
    • An example is to use more omega-3 fats to reduce gene expression of inflammatory cytokines
    • Public Health messages
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12
Q

What are the benefits of Nutritional Genomics?

A
  • There maybe dietary factors such as cruciferous vegetables (broccoli etc) that circumvent certain limitations caused by common gene variants
  • These dietary changes may be possible to implement across the spectrum if the response is highly prevalent in a population
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13
Q

What toos are used in Nutrigenomics?

A
  • Commonly the microArray
  • Exome sequencing
  • Deep sequencing (the only method to identify most RNAs)
  • Bioinformatic Analysis
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14
Q

What is Nutritional Epigenetics?

A
  • Changes in gene expression that does not involve changes in nucleotide sequence
  • Chemical tags are put on the DNA sequence or on proteins such that expression from the genome is altered
    • Include methylation of DNA and acetylation of proteins
    • Methylation occurs at cytosine residues often preventing gene expression
    • Acetylation is the addition of acetyl groups to the histone proteins keeping DNA closed or opened for translation
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15
Q

What is the carrier frequency?

A
  • How often the allele (variant) occurs in a population
  • Variation in a population may influence health care policy and medical practice
    • PKU as an example: screening occurs in all newborns, states regulate screening
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