Lecture on Nature, Nurture, and Epigenetics

Introduction

• Overview of two identical twins, Lucky Lyle and Trouble Tim, raised in different environments leading to different outcomes.
• Emphasis on the debate between genetic inheritance (nature) and environmental influence (nurture).

Historical Context

• Early beliefs had supernatural explanations for human traits.
• Transition to scientific explanations with the advent of social sciences and biological sciences.
• Nurture theory: Environment shapes an individual.
• Nature theory: Genes are the unchangeable blueprint.

Epigenetics

• Emerging field that suggests an interaction between nature and nurture.
• Defined as 'above genetics', studying how environmental factors can alter genetic expressions.

Case Study: Rat Mamas

• Research by Michael Meaney on maternal care in rats.
• High-licking vs. low-licking rat mothers observed.
  • High licking is associated with better maternal care.
  • Behavior is passed through generations.
• Experiment with fostering showed:
  • Genetic predisposition doesn’t determine maternal behavior.
  • Adopted rat babies from low-licking mothers raised by high-licking mothers exhibited high-licking behavior.

Genetic and Epigenetic Findings

• Methyl groups attached to genes regulate the expression of behaviors.
  • High-licking mothers cause the removal of methyl groups, activating certain genes in their babies.

Implications for Humans

• Similar epigenetic principles apply to humans, including Lucky Lyle and Trouble Tim.
• Lifestyle and environmental influences such as nutrition, exercise, smoking, stress, and love affect biological changes.
• Epigenetic changes can be observed at the DNA level.
• These changes occur throughout life, highlighting the impact of choices on human development.

Conclusion

• The interaction between genes and the environment, as shown by epigenetics, explains the differences in behavior and development seen in individuals with identical genetic makeup.
• Encourages mindful lifestyle choices as they can have lasting effects on our biological and psychological well-being.