Genetics

I.B. Learning Outcomes B11- With reference to relevant research

studies, to what extent does genetic inheritance influence behavior?

I can explain how much our genes impact our behavior.

Behavioral Genetics The study of how the both genetics and

the environment contribute to individual variations in human behavior.

Genes do not cause behavior, they create a predisposition towards it. Depression

Definition of a GeneGenes are the working subunits of

DNA. Each gene contains a particular set of instructions, usually coding for a particular protein or for a particular function.

Inheritance Each offspring inherits traits from their

parents. 46 Chromosomes – 23 from Mom, 23

from Dad ~20,000-25,000 genes

Key ideas about Genetics Genes that we inherit from our parents

give rise to physiological functions which contribute to physical and behavioral characteristics.

One Gene does not lead to a behavior, it can be a building block towards that behavior.

Twins

Separated Twin Studies Identical Genetic Make Up Different Environments Look for similarities and differences

between monozygotic twins Nature & Nurture Is It All In the Genes?

Minnesota Twin Study:Bouchard et al. (1990)

Learning Outcome: B11 Aim: To determine the extent that genetics

impact the behavior. Method:

Participants: Self-Selected MZ twins reared together (MZT) and MZ twins that were reared apart (MZA)

Performed 50 hours of interviews, tests, and surveys on participants.

Minnesota Twin Study:Bouchard et al. (1990) Cont.

Findings: Intelligence testing showed that 70% of intelligence

is attributed to genetic variation. Conclusions:

Intelligence among other characteristics are to a large extent due to genetics

Critical Thinking?

5-HTT Gene A gene that is responsible for creating

proteins that influence the reuptake of serotonin Long-Allele (57% of population) Short-Allele (43% of population)

Caspi et al. (2003) Learning Outcome: B11 Aim: To determine whether the 5-HTT gene

predicts depression Method:

Followed a group of adolescents for several years and measured for stressful events.

When they were 26, they tested them for depression.

Caspi et al. (2003) Findings:

Individuals who had a two short 5-HTT alleles were more likely to be depressed following stressful events.

Conclusion: Genetics can predict the likelihood of

depression in individuals. Critical Thinking?

Levenson (2013) Aim: To determine the role of the 5-HTT gene in marital

satisfaction

Method: Followed couples since 1989 and surveyed them on marital satisfaction.

Finding: Individuals with a short 5-HTT allele were more likely to be unhappy in an unhealthy relationship or happy in a healthy relationship.

Conclusion: Short Allele = More influenced by environment.

Critical Thinking?

COMT Gene COMT Gene: A gene that codes for an

enzyme that clears dopamine from the frontal lobe.

This can impact how you deal with stress.

Warrior or Worrier?Worrier:Slow Acting Enzyme

No Stress: Higher cognitive functioning, attention, and problem solving.

Stress: Meltdown

Warrior:Fast Acting Enzyme

No Stress: Underwhelmed by daily life and a lack of problem solving & concentration.

Stress: Concentration & Problem Solving Sky Rocket.

Chang et al (2009) Aim: To investigate the role of the COMT

Gene in test performance.

Method: Took blood samples from thousands of

Taiwanese students about to take their Basic Competency Test.

Performed a genetic test on each student. Compared the scores for variants of COMT

Gene.

Chang et al (2009) Finding: Students with fast acting enzymes

(warriors) performed better than students with slow acting enzymes (worriers).

Conclusions: The COMT gene impacted the way that students performed under a stressful situation.

Critical Thinking?

Parasuraman et al (2013) Aim: To investigate the COMT Gene’s impact on

high stress multitasking. Method:

99 participants were measured on their ability to control six drones in an airforce simulation.

Findings: Participants with the slow action enzyme (Worriers)

destroyed more targets than participants with fast acting enzymes (warriors).

Conclusion: People with slow acting enzyme variants were more effective at multitasking complex tasks,

Critical Thinking?

Ethics of Genetic Research Anonymity and Confidentiality.

Right to know who owns their genetic material and with whom it will be shared.

Informed Consent

Genetic research could potentially be a risk to the participants if misused.

Genetic Research can reveal information that is unexpected or a source of distress (Learning that you are predisposed to depression can lead to depression)

Discussion Questions Should the military, colleges, police forces, etc.

use genetic testing to help judge applicants?

Is it ethical to use genetics in determining who can become a drone pilot or another job?

Do you want a genetic test? Why or why not?

To what extent do our genes impact our behavior?