Test 1 - Neuroepigenetics Flashcards
When we say nature vs. nurture to what do nature and nurture refer?
Nature refers to genetics and nurture refers to environment
Are innate behaviors completely controlled by genetics?
No, innate behaviors are not 100% controlled by genes. Innate behaviors also called instincts can be altered in lab settings and then passed down to offspring such as the mice & ferret urine study.
What is neural plasticity?
Axons and dendrites (processes) can grow towards each other or shrink away from each other
- changing of neural networks
- environment has effect on nerve communication
What is the difference between monozygotic and dizygotic twins and which kinds of studies would you use each for?
Monozygotic: 2 embryos from same egg that splits - identical - epigenetics studies
Dizygotic: 2 separate eggs fertilized from 2 different sperm - fraternal - genetics studies
In studies with monozygotic twins that were separated at birth - can you 100% say that any differences are due to epigenetic changes?
No, you can not say that 100% because of mutagens.
Define epigentics.
Changs in phenotype without change in genotype found in the histones & DNA methylation (chemical marks on DNA)
What enzyme does DNA methylation?
DNMTS - DNA Methyl transferases (transfer methyl groups to DNA)
What happens when there is too much DNA methylation?
Too much DNA methylation is typically associated with gene silencing, since protein transcription is blocked
What enzyme type adds a hydroxyl group to methylated cytosines
TET enzymes (10-11 translocase)
What is the eventual result of hydroxymethylated DNA and what is its effect on gene expression?
TETs induce hydroxy methylation which is a conversion of methylated DNA back to unmethylated resulting in an increase in gene expression
What is a histone?
Protein in the nucleus that DNA wraps around (how we can have so much DNA in a small are)
What are the two possible modifications of histones?
- location of the modification
- how many methyl groups added
What enzyme types do the modifications to histones?
- HMTs (histone methyl transferases): methylation and demethylation
- HATs (histone acetyl transferases) & HDACs (histone deacetylase): acetylation and deacetylation
When histones are acetylated, what effect does this have on gene expression?
Acetylated histones have an increase in gene expression because they are wrapped less tightly
When histones are methylated, what effect does this have on gene expression?
Methylated histones have a decrease in gene expression because they block transcription from occurring.
What does it mean that an RNA is non-coding?
Non-coding is an RNA that is not going to be translated into a protein
Explain how miRNA regulates expression of a gene.
When miRNA binds to a portion of mRNA it signals RISC to bind and degrade the mRNA. This removes the mRNA and its protein cannot be transcribed resulting in a decrease of gene expression.
What are possible environmental factors that influence epigenetic marks?
- diet (folic acid; B12)
- chemicals (BPA; drugs)
- abuse; neglect
- maternal immune response (flu during pregnancy, etc.)
What can you say about epigenetic marks between regions of the brain?
Epigenetics most likely influences or causes different brain regions (neural plasticity) - There are increased levels of DNA methylation/hydroxymethylation between brain regions
Neuroethology
study of animal behavior in the natural environment
What is a big factor in neural plasticity and it efficacy?
age - after 26 new neurons can not regenerate
What were the 3 examples discused about neural plasticity and innate behaviors?
- ferret urine with rats
- chick hawk vs goose
- owls with prisms
Mutagen
something that changes the DNA sequence (changes actual DNA)
Heritability
the difference between monozygotic and dizygotic twins (how well does the trait correlate between them
MECP2
protein that likes to bind to methylated cytosines of DNA - MECP2 binds to methylated and just sits there which blocks the transcription factor proteins from reaching the promoter
What are the 4 types of histones?
- H2B
- H2A
- H4
- H3
What is the amino acid that generally receives modifications?
K - lyseine
Chromatin state
how tightly DNA is wrapped around histones
How to name histone mods - H3K4me1
H3 = histone type
K = amino acid location
4 = residue (location of a.a.)
me = type of mod (me vs. ac)
1 = # of mods (ac always blank)
acetylation always active
RISC
RNA induced silencing complex - binds to miRNA bound to UTRs and degrades the mRNA
miRNA-132
when it is decreased - HDAC1 & DNMT3A increase - and gene expression decreases - found in schizophrenia and autism development
