what is epigenetics
study of how the genotype and environment act together to make up the phenotype
examples of epigenetics
why identical twins aren’t actually identical
stress memory improving drought tolerance
inherited fear behaviour in rats
does epigenetics entail a change in DNA sequence
no
types of epigenetic modification
- histone modification
- DNA methylation
- non-coding RNAs
how many histone modifications are known
100
types of histone modification
- methylation
- acetylation
- citrulination
- phosphorylation
- ubiquination
in H3K27me3, what is represented by the H3
histone iD
in H3K27me3, what is represented by the K
amino acid iD
in H3K27me3, what is represented by the 27
AA position on tail
in H3K27me3, what is represented by the me3
chemical modification
histone modifications have different outcomes depending on:
- modification itself
- genomic location of mod
- presence of other modifications on same genomic location
what enzyme is involved in DNA methylation in mammals
DNA methyltransferase
what base is most often methylated
C
genomic regions rich in CpG prone to methylation are known as and are often associated with
CpG islands associated with promoter regions
what is the usual effect of DNA methylation
inhibit gene expression
are non-coding RNA’s direct or indirect modulators of epigenetic regulation
both
what treatment is used to detect DNA methylation and how does it work
bisulfite treatment
converts non-methylated cytosine into thymine
what is used to detect DNA-protein interaction (histone modifications)
chromatin immunoprecipitation (ChIP)
what are the steps of chromatin immunoprecipitation (ChIP)
- crosslink DNA proteins and isolate
- immunoprecipitate with specific antibody
- remove crosslinks and purify DNA
- peak calling
what is the role of the last step (peak calling) in ChIP
identify regions of the genome associated with specific histone modifications
what method is used to detect non-coding RNA (steps)
- extract total RNA
- enrich ncRNAs
- high throughput sequencing
- align to genome or ncRNA sequences
- annotate and quantify ncRNAs
what are the benefits of stress memory in plants
protection against future stress
local acclimation to changing environment
