behavior l.
Skip this Video
Loading SlideShow in 5 Seconds..
Behavior PowerPoint Presentation
Download Presentation

Loading in 2 Seconds...

play fullscreen
1 / 42

Behavior - PowerPoint PPT Presentation

  • Uploaded on

Behavior. Chapter 12. Central Points . Behavior is a reaction to environment Animals and humans have similar behaviors Brain chemicals important in human behavior Single gene or groups of genes can affect behavior Twin studies are an important part of behavioral genetics. 12.1 Behavior.

I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
Download Presentation

PowerPoint Slideshow about 'Behavior' - satchel

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript


Chapter 12

central points
Central Points
  • Behavior is a reaction to environment
  • Animals and humans have similar behaviors
  • Brain chemicals important in human behavior
  • Single gene or groups of genes can affect behavior
  • Twin studies are an important part of behavioral genetics
12 1 behavior
12.1 Behavior
  • A reaction to stimuli
  • Human behavior similarities to animal behavior, response more variable, difficult to study
  • Behavioral genetics: study of the influence of genes on behavior
  • Which more important: genetics or environment?
12 2 n eurotransmitters
12.2 Neurotransmitters
  • Brain chemicals that can change our moods and actions
  • Neurotransmission: Neurotransmitters released when certain neurons in the brain fire
  • Impulse travels to synapse, neurotransmitter is released
  • Increases or decreases in the release of the neurotransmitter, may change behavior
12 3 changes in genes changes behavior
12.3 Changes in Genes Changes Behavior
  • Chromosomal abnormalities, single-gene defects, and multigenic conditions can alter behavior

Example of single-gene defect: Huntington disease (HD)

  • Codes for protein huntingtin, necessary for the survival of certain brain cells
  • Symptoms of HD: involuntary movements and progressive personality changes
chromosomal abnormalities
Chromosomal Abnormalities
  • Example: fragile X syndrome mutation on X chromosome
  • Causes autistic typebehaviors as well as problems with aggression
schizophrenia a multifactorial condition
Schizophrenia: A Multifactorial Condition
  • Many symptoms including hallucinations, delusions, disordered thinking, changed behavior
  • Genes associated with schizophrenia found on X chromosome and other autosomes
  • Also possible environmental component
12 4 studying the genetics of behavior
12.4 Studying the Genetics of Behavior
  • Search to find the genetic influences
  • Multiple backgrounds:





molecular geneticists

identical twins monozygotic
Identical Twins (Monozygotic)
  • Identical twins have identical genomes
  • If a specific trait or behavior is same in both twins, most likely significant genetic component
  • If twins raised in separate environments and have different behavioral traits, traits have a significant environmental component
concordance in monozygotic twins
Concordance in Monozygotic Twins
  • If one identical twin is alcoholic, 55% chance other twin will be alcoholic regardless of environment
  • Concordance: how often a trait occurs in both members of a pair of twins
  • Genetic trait, cystic fibrosis concordance = 1.0
  • Concordance helps establish whether or not trait has genetic basis
animal studies 1
Animal Studies (1)
  • Mice reproduce quickly, behaviors are observable
  • May use recombinant DNA techniques
  • Insert a human gene
  • Mutate a mouse gene
  • Change gene’s pattern of expression
animal studies 2
Animal Studies (2)
  • Human gene for a protein associated with memory inserted into mice
  • Transgenic mice improved maze running and other tests
genetic causes of sexual orientation
Genetic Causes of Sexual Orientation
  • Used twin studies, chromosomal analysis, and pedigree analysis
  • Suggest genetic component to homosexual behavior
  • Used linkage and pedigree studies to ID area on X chromosome associated with homosexuality
  • Foundation for further work on genetics and homosexuality
12 5 single gene defect and aggressive behavior
12.5 Single-Gene Defect and Aggressive Behavior
  • Large family with aggressive and violent behavior
  • Only in men, many committed violent offenses
  • Mapped to short arm of X chromosome
  • Gene encodes monoamine oxidase type A (MAOA) that breaks down neurotransmitters
  • Mutated form of gene, MAOA deficiency
knock out mice for serotonin receptors
Knock out Mice for Serotonin Receptors
  • Failure to rapidly break down neurotransmitters such as serotonin
  • Can cause abnormal behavior
  • Researchers deactivate (“knock out”) serotonin receptor gene in mouse
    • Knockout mouse aggressive to unfamiliar mouse
12 6 legal and ethical issues
12.6 Legal and Ethical Issues
  • Not sure what causes aspects of behavior
  • Courts finding it difficult to deal with topic
  • Experts do not agree on findings, individual courts cannot decide how it will be used
  • If certain genes or groups of genes cause someone to commit a crime, motive no longer relevant
xyy syndrome
XYY Syndrome
  • Prisoners incarcerated for violent crimes showed higher percentage of men with XYY syndrome
  • Studies done on relationship between criminality and XYY individuals
  • Generally taller and perhaps more aggressive, but this does not mean they are criminals
  • Information incomplete
case a twins found strangely alike
Case A: Twins Found Strangely Alike
  • University of Minnesota Twin Study Group, studying twins reared apart
  • “Two Jims”: amazing number of physical and other similarities
  • Twin studies assist in the study of the genetics of behavior
case a questions
Case A Questions
  • Why were these two men a perfect set of twins to study behavior?
  • Do you think the evidence shows the behaviors listed in the case are 100% genetic?
  • Can you see any problems studying twins raised apart?
  • See the textbook for further questions on this case
case b important conference on hold
Case B: Important Conference on Hold
  • “Genetic Factors in Crime: Findings, Uses, and Implications”
  • Protests caused meeting to be cancelled
  • What should the scientists do?
  • What are the important issues?
  • See the textbook for further questions on this case
1966 richard speck
1966: Richard Speck
  • Tried and convicted of killing eight student nurses
  • Attorney prepared defense trying to use XYY karyotype as argument against death penalty
  • Speck did not have the XYY karyotype
  • Many unanswered questions about genetics and behavior remain
other questions
Other Questions
  • If criminal or antisocial behavior is genetically controlled, how can someone be rehabilitated?
  • Roper v. Simmons: an amicus curiae brief presented
    • Area of brain controlling impulsive behavior underdeveloped in teens
    • Therefore unable to realize actions
  • Most judges and juries considered genetic predisposition to crime junk science
spotlight on law mobley v georgia
Spotlight on Law: Mobley v. Georgia
  • Stephen Mobley on trial
    • Violent murder and armed robbery at Domino’s
    • History of rape, robbery, assault, and burglary
    • Aggressive behavior prevalent in his family
    • Wanted to be tested for mutation of MAOA gene
  • Court denied, genetic connection not at level of scientific acceptance to justify its admission
spotlight on law questions
Spotlight on Law: Questions
  • Women in Mobley’s family are identified with trait. Could this be MAOA deficiency?
  • Would you have allowed the testing?
  • How does this relate to a genetic cause of crime?
  • See the textbook for further questions on this case