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What Is Epigenetics ?

What Is Epigenetics ?. Shirish Barve Professor Department of Internal Medicine Division of Gastroenterology/Hepatology. The term ‘epigenetic’ refers to all heritable changes in gene expression and chromatin organization that are independent of the DNA sequence itself.

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What Is Epigenetics ?

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  1. What Is Epigenetics ? Shirish Barve Professor Department of Internal Medicine Division of Gastroenterology/Hepatology

  2. The term ‘epigenetic’ refers to all heritable changes in gene expression and chromatin organization that are independent of the DNA sequence itself.

  3. Epigenome provides instructions and regulates the functional aspects of all the genes

  4. Scientists Find Clue To Mechanisms Of Gene Signaling And Regulation(Aug. 23, 2007) Epigenetics To Shape Stem Cell Future(Feb. 23, 2007) Human Embryonic Stem Cells Remain Embryonic Because Of Epigenetic Factors(Oct. 8, 2007) Epigenetic Changes Discovered In Major Psychosis(Mar. 12, 2008) Epigenetics May Be The Underlying Cause For Male Infertility(Dec. 13, 2007)

  5. Monozygous twins share a common genotype and are genetically identical • There is significant • phenotypic discordance: • Mental disorders • Cancer

  6. Transcriptionally active chromatin regions tend to be hyperacetylated and hypomethylated.  If a region of DNA or a gene is destined for silencing, chromatin remodeling enzymes such as histone deacetylases and ATP-dependent chromatin remodelers likely begin the gene silencing process.  One or more of these activities may recruit DNA methyltransferase resulting in DNA methylation, followed finally by recruitment of the methyl-CpG binding proteins. The region of DNA will then be heritably maintained in an inactive state.

  7. Age Dependent Epigenetic differences in Monozygotic (MZ) twins

  8. Influence of Age on the Epigenome in MZ Twins • In the early years of life the younger MZ twins are epigenetically indistinguishable • Older MZ twins exhibit remarkable differences in their epigenome as evidenced by changes in the: • overall content and genomic distribution of 5-methylcytosine DNA and • histone acetylation, affecting their gene-expression portrait.

  9. Epigenetics stands at the center of modern medicine because epigenetic changes, unlike DNA sequence which is the same in every cell, can occur as a result of dietary and other environmental exposure

  10. Environment &Epigenome Mounting evidence suggests that fetuses are surprisingly susceptible to outside influences such as environmental pollutants, pesticides, and other toxins.

  11. Agouti “Twin” Sisters

  12. Coat color serves as a sensor for the degree of methylation present

  13. Bisphenol A

  14. Bisphenol A

  15. Bisphenol A

  16. Bisphenol A

  17. Bisphenol A

  18. With minor exceptions, all differentiation processes are triggered and maintained through epigenetic mechanisms.

  19. Epigenetic inheritance is an essential mechanism that allows the stable propagation of gene activity states from one generation of cells to the next.

  20. DNA Is Not Destiny The new science of epigenetics rewrites the rules of disease, heredity, and identity.

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