Epigenetics Flashcards
Define epigenetics
study of how gene activity can be controlled without changing the DNA sequence itself
What can cause changes to underlying DNA?
-polymorphism
-mutation-consequential
What does epigenetics do?
-regulates gene effectively- on/off
-changes how the genome is read
-assignment through imprinting introduces randomness- to keep resilients
-behaviours and environmental factors can cause regulatory changes that affect the way genes works
What is DNA methylation?
-DNA methylation works by adding a chemical group (Methyl group) to tag the DNA ( can activate or repress genes)
cytosine and adenine nucleotides can be methylated but exclusively methylation only occurs in the CpG dinucleotides
What factors affect the epigenetics mechanisms?
-development in utero and childhood
-environmental chemicals
-pharmaceuticals
-aging
-diet
epigenetic factors respond to environment and transcend generations- e.g dutch hunger winter famine 1944-1945
What is histone modification?
the binding of epigenetic factors to the histone tails alters the extent to which DNA is wrapped around histones and the availability of genes in the DNA to be activated
Give some examples of epigenetic triggers
-toxic chemicals
-diet
-psychological state
-microbiome
-therapeutic drugs
-disease
-infection
-excersise
These factors can tag the DNA to help/hinder accessibility- promoting or inhibiting gene activation
What are some examples of histone modification mechanisms?
-acetylation/deacetylation
-methylation
-ubiquitylation
-phosphorylation
-biotinylation
-sumoylation
What things makes epigenetics helpful?
1-better understanding the pathogenesis
2-formation of disease pattern
3-develop new approaches to the pathology diagnostics and treatment
-may only need methylation sequencing
-treatment may require via negative
-opportunity to approach treatment in novel ways - turn on/off genes instead of altering DNA
Describe the genes involved with dilted cardiomyopathy
gene GADAD1 is weakly associated to epigenetic changes in the chromatin organisation and modelling
Describe the genes involved with hypertrophic cardiomyopathy
Gene SLC254A has a proven epigeneteic impact affecting the maintenance of mitochondrial genome stability
Give an example of where epigenetics assists in subtyping the condition phenotype
Thoracic aortic aneurysm
TAA to biomechanical stimuli, such as ageing or genetic/biochemical alterations of aortic wall protein constituents
Describe the process of DNA replication
-H bonds break and strands seperate
-Catalysed by DNA helicase
-both strands act as a template
-free DNA nucleotides attach forming complementary base pairs
-A-T C-G
-DNA polymerase joins nucleotides
-This is called semi conservative replication
Describe the process of transcription
-DNA helicase
-breaks H bonds of a gene
-only one DNA strand acts as a template
-RNA nucelotides attracted to exposed bases according to base pairing rules
-A-U, T-A, C-G, G-C
-RNA polymerase joins RNA nucleotides together
-pre mRNA spliced to remove introns
Describe the process of translation
-Ribosomes attach to mRNA
-idea of two codons/binding sites
-ribosomes move to start codon (AUG)
-tRNA brings a specific amino acid
-tRNA anticodon is complementary is mRNA codon
-ribosome moves along next codon
-process repeats and AA join by peptide bonds to form polypeptide using energy from ATP
