Understanding Epigenetics in Biology

Sep 23, 2024

Biology Lecture Notes: Epigenetics

Introduction to Complexity in Biology

  • Biology is complex and often misunderstood at first glance.
  • Example: Eye color, initially taught as simple, is polygenic (many genes involved).
  • Even traits like earlobes are not as simple as they appear.

Epigenetics Overview

  • Epigenetics: Study of changes in gene expression without altering DNA sequence.
  • DNA is influenced by epigenetic factors which affect physical traits.

Key Concepts in Epigenetics

  • Identical Twins: Same DNA but can have different disease outcomes due to epigenetic factors.
  • Epigenetic Marks: Influence gene activity and expression.
    • Methylation: Methyl groups attach to DNA, preventing transcription.
    • Demethylation: Removal of methyl groups, allowing transcription.
    • Histones: Proteins DNA wraps around; subject to epigenetic modifications.
      • Histone Methylation: Prevents transcription.
      • Histone Acetylation: Loosens DNA packing, allows transcription.
      • Histone Deacetylation: Tightens DNA packing, limits transcription.

Examples of Epigenetics in Animals

  • Rodent Maternal Care: Licking/grooming by mother rats affects stress response in offspring via GR gene expression.
  • Agouti Trait in Mice: Diet of pregnant mice can affect offspring traits via methylation of agouti gene.

Inheritance of Epigenetic Marks

  • Cell Division: Epigenetic marks passed from parent to daughter cells during mitosis.
  • Fertilization: Most marks are cleared, but some can be inherited from parent to offspring.

Internal vs. External Influences

  • Epigenetic marks influenced by both environmental and internal cues.
  • Different cell types express different genes due to epigenetic factors.

Importance of Epigenetics

  • Significant role in diseases like cancer.
  • Epigenetic therapy aims to treat diseases by modifying epigenetic marks.
  • Understanding epigenetics aids in comprehending cellular and bodily functions.

Conclusion

  • Epigenetics is a rapidly advancing field with potential for significant medical breakthroughs.
  • Encouragement to remain curious and continue exploring biology.