Biological Domains

Biological Domains

Genes and Behavior​

By Sandra Jackson

Introduciton

​Biological Domains

These are the physical elements and biological systems that influence and can be influenced by our behaviors, thoughts and feelings.

​

This presentation will focus on the genetic influence on behavior and discuss the traditional studies of behavioral genetics.

Larsen, Randy, et al. Personality Psychology: Domains of Knowledge about Human Nature. McGraw Hill, 2021. Pg 48

What are Genes?

• ​Genes

  • ​Are the parts of DNA that code for a trait.

    • Example; blonde hair, black hair, blue eyes, brown eyes

• The Genome

  • All the genes that make up an organism.

    • Humans have 20,000 - 25,000 genes

  • We get 50% from Mom and 50% from Dad.

  ​

​

Larsen, Randy, et al. Personality Psychology: Domains of Knowledge about Human Nature. McGraw Hill, 2021. Pg 50

Open Ended

What traits did you inherit from your parents? Did you get your father’s nose? Or your Mom’s eyes? If you are comfortable please share an example of a trait you know for certain you received from your mom or dad?

Behavioral Genetics

• The study of how genetics impact behavior.

• People who study this are called Behavioral Geneticists.

​

What do Behavioral Geneticists look for?

1. ​Percentage of Variance

   • Individuals vary from one another and these variances can be quantified into percentages based on different causes.

2. Finding out how genes and the environment interact and correlate to each other.

3. Finding out and determine the impact of where these environmental changes occur.

Subject | Subject

Larsen, Randy, et al. Personality Psychology: Domains of Knowledge about Human Nature. McGraw Hill, 2021. Pg 52

​4 Traditional Behavior Genetic Methods

1. ​Selective breeding studies.

2. Family studies.

3. ​Twin studies.

4. Adoption Studies. ​

Selective Breeding

• ​These studies have been conducted for generations on dogs.

• Dog breeders select for certain traits

  • Temperament, aggression, agreeableness, etc.

• Dogs are selected for desired straits and are breed. Puppies should have some if not all of the desired traits.

  • Eventually, if enough change happens we get a new dog breed. ​

Subject | Subject

Larsen, Randy, et al. Personality Psychology: Domains of Knowledge about Human Nature. McGraw Hill, 2021. Pg 54

Family Studies

• ​Based on the idea that offspring should share 50% of each parents genes, 25% of grandparents genes and 12.5% of cousins genes.

  • If trait is highly hereditable than it should be present in one or more members of the family.

  • Caveats, not all members of the family are exactly 100% similar also, environment may be a definitive factor

    • If offspring are shy they may have learned from parents.

Subject | Subject

Larsen, Randy, et al. Personality Psychology: Domains of Knowledge about Human Nature. McGraw Hill, 2021. Pg 54

Twin Studies

• ​Monozygotic Twins share 100% Identical

  • Known as identical twins

• Dizygotic Twins share 50% DNA

  • Act like regular siblings. ​

• Identical twins studies have shown that 90% of characteristics are hereditable.

  • May dress the same, have same hand dominance, have same interests in sports or music.

Subject | Subject

Larsen, Randy, et al. Personality Psychology: Domains of Knowledge about Human Nature. McGraw Hill, 2021. Pg 54

Adoption Studies

• ​These studies look at how twins separated at birth and are thrust into different environments have any similarities in personality, traits, life outcomes.

• Benefit

  • Gets around equal environment assumption in which twins are treated the same and are in same environment so they should end up similar.

Subject | Subject

Larsen, Randy, et al. Personality Psychology: Domains of Knowledge about Human Nature. McGraw Hill, 2021. Pg 54

Advantages and limitations of each Method

Subject | Subject

Larsen, Randy, et al. Personality Psychology: Domains of Knowledge about Human Nature. McGraw Hill, 2021. Pg 54

Final Thoughts

​The traditional studies have focused on how our environment can influence our personality while keeping in mind how our genetic tendencies influence the level of which the environmental factors amplify specific personality traits.

​

The last video talks about a field called epigenetics in which nature vs nurtures is tested based on gene expression, which is when genes are turned on or off depending on our environment. ​

Subject | Subject

Some text here about the topic of discussion

Review Questions.

Multiple Choice

What percentage of genes do you receive from your mom or dad?

• 25%

• 75%

• 100%

• 50%

Multiple Choice

Which of these is not a traditional study of behavioral genetics.

• Molecular Studies

• Family Studies

• Twin Studies

• Adoption Studies

Multiple Choice

This part of DNA codes for a specific trait.

• Proteins

• Genes

• Abilities

• RNA