382: Stress and Epigenetics

1. Epigenetics History
1. James Watson & Francis Crick
1. Discover the structure of DNA (1953)
2. Crick
1. The Central Dogma
1. DNA to Transcription to RNA to Translation to Protein
2. a.k.a. Genetic Determinism
1. Thought that if you understand genes then you basically understand everything
2. Genes
1. Control reproduction and day-by-day function of all cells
2. Genes control cell function
2. Claude Bernard
1. “It is that which we do know which is the greatest hindrance to our learning, not that which we do not know.”
2. Epigenetics
1. Definition
1. Heritable changes in gene expression that do not involve a change in DNA sequence
2. Bridge between genotype and phenotype
1. Genotype
1. genes
2. Phenotype
1. expression
3. Environment, perception, and behavior affect gene expression
1. Genes to Proteins to Structure of Nervous System to Behavior which are all affected by environment, perception and behavior
2. Chromatin
1. Epigenetic material
3. Methylation and Histone Modification
1. DNA Methylation
1. The attachment or substitution of a methyl of a mehtyl group for another compound
2. in genetics, methyl marks are added to certain DNA bases which repress gene activity
3. Think of it as looking at ONE gene and silencing that ONE gene
2. Histone Modification
1. DNA are wrapped around histones in order to save space in the nucleus
2. If histones don’t unwrap then DNA cannot be read
3. This is looking at a bunch of DNA instead of just one.
4. STUDIEs
1. Jirtle
1. Agouti gene: cute fat mice w/ yellow fur
2. Soy contains methyl donors (hypothesized to play a role in asiands having better health)
3. Pregnant agouti moms eating soy diet have skinny kids with dark fur
4. Soy diet silenced the agouti gene
2. Afroga Study
1. Diff between histones and methyl marks
3. Michael Meaney
1. Talk about how he stressed out the rats, rat pups were more susceptible to stress, and epigenomic state of a gene can be established through behavioral programming (stress out the mom) and it is potentially reversible