chapter 2

Influence of Genes and Behavior

• Genetics and behavior are interconnected, with genes affecting behavior and behavior influencing gene expression.

• Environmental factors play a significant role, including:

  • Home environment

  • Family dynamics

  • School interactions

Extroversion vs. Introversion

• Traits like extroversion and introversion are influenced by both genetic predispositions and environmental factors.

• Example: A person might have a genetic predisposition for extroversion but their environment (friends, family) can further reinforce or inhibit these traits.

• Personal anecdote:

  • The speaker identifies as extroverted, enjoying social interactions (e.g., talking to two people on a plane).

  • Contrast with a partner who is introverted and prefers not to engage with strangers.

Gene-Environment Interplay

• The interaction between environment and genetics is complex, impacting behavioral tendencies.

• Genes can be altered by environmental influences, leading to changes in behavior.

Methylation

• Methylation is a biological process that modifies gene expression.

• It should not be confused with myelination, which relates to forming the myelin sheath around neurons.

• Environmental stressors can affect methylation, thus altering how genes function in response to such influences.

Research and Implications

• Important research points include:

  • The impact of maternal habits (e.g., smoking during pregnancy) on child development.

  • Studies show that children whose mothers smoked during pregnancy may have an increased risk of developing ADHD due to specific genetic markers (chromosomes).

• This illustrates the long-lasting effect of early environmental factors on genetic expression and behavior.