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C. H. Waddinton coined the phrase
“epigenetics” in the 1940’s to describe how
environmental influences on developmental
ev...
Stable, mitotically and meiotically heritable
phenotypes that result from changes in gene
expression without alterations i...
is the study of the ways in
which epigenetic traits
alter cell and tissue
specific patterns on gene
expression
Gene expression uses reversible modifications
of DNA and chromatin structure to mediate the
interaction of the genome with...
The epigenetic
state of the cell
An organism has
one genome
Genome can be
modified in
diverse cell types
at different time...
The epigenome can be transmitted to daughter
cells via mitosis and to future generations via
meiosis
Mechanisms of epigene...
Three major epigenetic
mechanisms:
Reversible modification
of DNA by the addition or
removal of methyl groups
Alteration o...
Addition of a methyl
group –CH3 to cytosine
Catalyzed by
methyltransferases
Almost exclusive next to
a Guanine, creating a...
The methyl groups in CpG
dinucleotides occupy the
major groove of DNA and
block the binding of
transcription factors
neces...
As part of dosage
compensation, one of the X
chromosomes in females is
inactivated
Converted to
heterochromatin
Altered pa...
The N-terminal region of each histone extends
beyond the nucleosome, and the amino acids in
these tails can be covalently ...
Histone acetylation - transcription
Reversible
Changing from “open” to “closed”
Ex. Lysine 9 on histone H3
A large number of histone modifications are
possible
The sum of the complex patterns and
interactions of histone modificat...
Noncoding RNAs that participate in epigenetic
regulation
Involved in controlling pattern formation in
developing embryos a...
miRNAs
contribute
to cardio-
vascular
disease
and
cancer
Transcribed as precursor
molecules about 70-100
nucleotides long
Contain a double-
stranded loop
Processing removes the
si...
Resulting double stranded RNA is incorporated
into a protein complex where one RNA strand is
removed and degraded
Forms a ...
Epigenetics
Epigenetics
Epigenetics
Epigenetics
Epigenetics
Epigenetics
Epigenetics
Epigenetics
Epigenetics
Epigenetics
Epigenetics
Epigenetics
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Epigenetics

Epigenetics

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Epigenetics

  1. 1. C. H. Waddinton coined the phrase “epigenetics” in the 1940’s to describe how environmental influences on developmental event can affect the phenotype of an adult
  2. 2. Stable, mitotically and meiotically heritable phenotypes that result from changes in gene expression without alterations in the DNA sequence
  3. 3. is the study of the ways in which epigenetic traits alter cell and tissue specific patterns on gene expression
  4. 4. Gene expression uses reversible modifications of DNA and chromatin structure to mediate the interaction of the genome with a variety of environmental factors and generates changes in the patterns of gene expression in response to these factors
  5. 5. The epigenetic state of the cell An organism has one genome Genome can be modified in diverse cell types at different times to produce many epigenomes What is the epigenome?
  6. 6. The epigenome can be transmitted to daughter cells via mitosis and to future generations via meiosis Mechanisms of epigenetic changes have a role in : Imprinting Cancer Behavior Environment-genome interactions
  7. 7. Three major epigenetic mechanisms: Reversible modification of DNA by the addition or removal of methyl groups Alteration of chromatin by the addition or removal of chemical groups to histone proteins Regulation of gene expression by small, noncoding RNA molecules
  8. 8. Addition of a methyl group –CH3 to cytosine Catalyzed by methyltransferases Almost exclusive next to a Guanine, creating a CpG dinucleotide CpG islands, often located in and near promoter sequences
  9. 9. The methyl groups in CpG dinucleotides occupy the major groove of DNA and block the binding of transcription factors necessary to form transcription complexes
  10. 10. As part of dosage compensation, one of the X chromosomes in females is inactivated Converted to heterochromatin Altered patterns of DNA methylation
  11. 11. The N-terminal region of each histone extends beyond the nucleosome, and the amino acids in these tails can be covalently modified Acetyl, Methyl, Phosphate groups Alter chromatin structure
  12. 12. Histone acetylation - transcription Reversible Changing from “open” to “closed”
  13. 13. Ex. Lysine 9 on histone H3
  14. 14. A large number of histone modifications are possible The sum of the complex patterns and interactions of histone modifications that alter chromatin organization and gene expression is called the histone code
  15. 15. Noncoding RNAs that participate in epigenetic regulation Involved in controlling pattern formation in developing embryos and developmental events Involved in cell signaling
  16. 16. miRNAs contribute to cardio- vascular disease and cancer
  17. 17. Transcribed as precursor molecules about 70-100 nucleotides long Contain a double- stranded loop Processing removes the single stranded regions Loops move to the cytoplasm Further altered in the cytoplasm
  18. 18. Resulting double stranded RNA is incorporated into a protein complex where one RNA strand is removed and degraded Forms a mature RNA-Induced Silencing Complex (RISC) Contains the remaining single miRNA strand

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