Lecture Notes on Epigenetics and Identical Twins

Identical Twins and Differences

• Identical twins have the same DNA, but they can develop differences over time.
• Differences can become more pronounced as they age.
• Example given: one twin may develop cancer while the other does not.

DNA and Genetics

• Twins start from the same egg, making them genetically identical, or clones.
• Identical twins' health may diverge despite having the same genes.

Epigenetics

• Epigenetics: Refers to the chemical changes that affect gene expression without altering the DNA sequence.
• New biological findings suggest that epigenetics play a crucial role in how genes are expressed.

Epigenetic Factors

• Methylation: Methyl groups (carbon and hydrogen) can attach to genes, turning them off.
• These chemical tags are part of what is known as the epigenome.
• The epigenome acts like software, instructing the genome (hardware) how to function.

Research Insights

• Randy Jle’s mice studies at Duke University:
  • Mice with identical genetic make-up showed different physical traits due to epigenetic changes.
  • Diet during pregnancy can alter the offspring's epigenome.
  • Example: Mice with dietary changes showed different coat colors and sizes.

Human Studies

• Spanish twins study (2005):
  • Examined how epigenomes of identical twins can differ.
  • As twins age, their epigenomes change, influenced by lifestyle factors like diet and smoking.

Implications for Health

• Epigenetic changes can trigger diseases such as cancer.
• MDS (Myelodysplastic Syndromes) linked to epigenetic changes.
  • Potential to use epigenetic therapy to reactivate genes and treat cancer.

Epigenetic Therapy

• Aims to alter gene expression rather than destroy cancer cells.
• Early clinical trials show promising results for patients in remission.

Responsibility and Hope

• Individuals can potentially alter their epigenome and that of their offspring.
• Encouragement to be mindful of lifestyle choices that impact epigenetic health.

Conclusion

• The study of epigenetics adds a layer of complexity to our understanding of genes and health.
• Offers new avenues for treatment and prevention of diseases.
• Highlights the importance of lifestyle choices in maintaining health.