Epigenetics - An Introduction

Epigenetics - An Introduction

Understanding DNA and Epigenetics

The Structure of DNA and Chromatin

  • There are over 100,000 skin cells in one square cm of skin, each containing nearly 2 meters of DNA that holds our genetic information.
  • The entire genetic material in our body is referred to as the genome; DNA is packaged with proteins called histones into a complex known as chromatin.
  • Chromatin condenses further to form chromosomes; humans have a total of 46 chromosomes stored in the nucleus.
  • Each nucleosome consists of DNA wrapped around an octamer of histone proteins (H2A, H2B, H3, H4), allowing for gene regulation within cells.

Gene Expression and Cell Differentiation

  • Despite all cells having the same DNA sequence, they exhibit different structures and functions due to selective gene expression.
  • Different cell types express specific genes while silencing others; for instance, muscle cells activate muscle-related genes while turning off liver-specific genes.

Epigenetic Modifications

  • Epigenetic modifications involve chemical tags on DNA or histones that influence gene expression without altering the underlying DNA sequence.
  • Two main types of epigenetic modifications are discussed:
  • DNA Methylation: Addition of a methyl group to cytosine residues in CpG sequences associated with gene silencing.
  • Histone Modifications: Acetyl or methyl groups added to histone tails affecting transcription activation or repression.

Developmental Patterns and Cancer Implications

  • Genome-wide patterns of these epigenetic modifications are established during early development and maintained through cell division.
  • Alterations in these patterns can lead to disruptions seen in cancerous cells.
Video description

Join the Community: https://armandoh.org/sp/beta-member/ This sketch video about epigenetics was created by Armando Hasudungan, in collaboration with Professor Susan Clark and Dr Kate Patterson at the Garvan Institute of Medical Research. It has been created for a broad, non-expert audience to highlight key messages about the role epigenetics plays in biological processes like development and diseases such as cancer. #epigenetics #genetics #molecularbiology #scienceeducation #medicallecture Social media: 📷 Instagram: http://instagram.com/armandohasudungan 𝕏: https://x.com/armandohasudung 📔Facebook: https://www.facebook.com/ArmandoHasudungan Our mission: We turn healthcare education from consumption into collaboration. Medical disclaimer: This content is provided for educational purposes only and is not intended as medical advice, diagnosis, or treatment. It should not be used as a substitute for professional clinical judgment or consultation with a qualified healthcare professional. Always seek the advice of your physician or other qualified health provider regarding any medical condition. © Visualising Medicine. All rights reserved.