Genetics

1. Genetics

2. 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.

3. 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

4. Definition of a Gene
Genes 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.

5. Inheritance
 Each offspring inherits traits from their
parents.
 46 Chromosomes – 23 from Mom, 23 from
Dad
 ~20,000-25,000 genes

6. 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.

7. Twins

8. 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?

9. 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.

10. 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?

11. 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)

12. 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.

13. 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?

14. 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?

15. 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.

16. 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.

17. 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.

18. 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?

19. 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?

20. 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)

21. 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?