Menon 2 Flashcards
Gene-environment interaction is defined as a different effect of an environmental factor in people with different ___________.
genotypes
___________ is an example of an environmental influence that can have different effects on individuals with different genotypes.
smoking
___________ is the study of heritable, reversible changes in gene expression or cellular phenotype caused by mechanisms other than changes in the underlying DNA sequence.
Epigenetics
___________ is a molecular mechanism that can couple the environment to genes.
DNA methylation
___________ of cytosine is a chemical modification of nucleotides that plays a role in epigenetics.
Methylation
List three roles of DNA methylation.
Transcriptional silencing
Protecting the genome from transposition
Genomic imprinting
___________ involves the addition of an acetyl group to a histone protein, which is associated with gene activation.
Histone acetylation
___________ acetylate histones, leading to chromatin opening and enabling transcription.
Histone acetylases (HATs)
Epigenetics provides a form of ___________ control of genes that is independent of DNA sequence.
transcriptional
True or False: The effects of epigenetics are heritable but reversible.
True
Epigenetics connects ___________ with adult disease.
nutrition
A famous example of a cohort study is _________.
the Boston nurse study
___________, the most common type of genetic variation among people, represents a difference in a single DNA building block, called a nucleotide.
SNP (Single nucleotide polymorphism)
What was the Boston nurse study?
A study where nurses were followed for 40+ years and tracked in order to learn about their health (development of diseases like chronic high blood pressure).
A ___________ is a group of SNPs on the same chromosome that are inherited together from a single parent.
haplotype
A ___________ SNP is a representative single nucleotide polymorphism (SNP) that represents a group of SNPs (haplotype).
Tagging
Give an example of a gene-environment interaction.
Individuals with different nicotine metabolism genotypes may have different susceptibilities to lung cancer when exposed to smoking.
___________ interaction occurs when an environmental exposure results in a larger effect in individuals with certain genotypes compared to others.
Synergistic
___________ interaction occurs when an environmental exposure results in a smaller effect in individuals with certain genotypes compared to others.
Antagonistic
Conrad Waddington’s 1945 experiments with ___________ demonstrated that phenotype can be significantly influenced by the environment.
Drosophila
___________ alleles in Drosophila wing and wing-vein development were influenced by temperature in Waddington’s experiments.
Temperature-sensitive
In Waddington’s experiment, incubating larvae from the same genetic strain of fruit fly at different temperatures resulted in different _______ phenotypes.
wing
Waddington’s experiment concluded that two different environments can act differently on the same ___________, causing different phenotypes!
gene
Waddington’s experiment on ___________ demonstrated that the effect of temperature on wing size is not permanent and can be reversed in subsequent generations.
transgenerational regression
Supplementation of maternal diet with ___________ can have an effect on coat color, illustrating the influence of environment on phenotype.
folate (vitamin B9)
Adverse environment in _______ is increasingly recognized as an important component in obesity and Type-2 diabetes.
utero
What makes one cell type different from another cell type, given that they have the same DNA?
While all cells in an organism have the same DNA, they can express different sets of genes, leading to different cell types. This differential gene expression is influenced by epigenetic modifications and other regulatory mechanisms.
True or False: The effects of the environment can depend on genetics, and the effects of genetics can depend on the environment.
True
___________ provides insights into how environmental factors can lead to changes in gene expression and contribute to complex diseases.
Epigenetics
What is a case study?
A case study is a short-term (ish) study that compares an experimental group to a control group.
What did Conrad Waddington call his model?
The pluripotent stem cell
In a cohort study, the risk of an outcome is calculated by dividing the number of individuals in a group who have the outcome by the total number of individuals in that group. Mathematically, this is represented as ___________ divided by ___________.
a/(a+c)
In a cohort study, the relative risk is calculated by ___________.
[Risk in exposed group] / [Risk in unexposed group] OR (a/(a+c)) / (b/(b+d))
The odds ratio is a measure of association used in ___________ studies.
case-control
In a case-control study, the odds ratio is calculated as ___________.
ad/bc
The odds ratio compares the ___________ of exposure to a certain factor among individuals with a specific outcome (cases) to the ___________ of exposure to the same factor among individuals without that outcome (controls).
odds; odds
Diseases with what shaped curve are best treated with environmental and lifestyle changes?
Those with a bell-curve distribution (mentioned orally on 10/8)
Diseases with what shaped curve are best treated with pharmacological intervention?
Those with a sharp curve/distribution (mentioned orally on 10/8)
