Genes and Crime

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Genes and Crime!
Dr. Matt Robinson CJ 3400 Theories of
Crime Appalachian State University
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Levels of Analysis
Cell
Organ
Organism
Group
Community/ Organization
Society
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Behavior in the contextof cells

• Cells are the basic units of which all living
  things are composed
• Cells coordinate functions and are the building
  blocks of organs and organisms
• Cells form organs so factors at cell level effect
  organs
• e.g., genes effect brain function

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Behavior in the contextof cells

• Main area of research at cell level is GENETICS
• Genes are biochemical part of cells that
  determine what cells become
• Genes determine WHAT you become
• cat, dog, monkey, human

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DNA

• Human body has 100 trillion cells
• Each cell contains human genome
• Blueprint to build a person
• Center of each living cell (nucleus) contains six
  feet of deoxyribonucleic acid (DNA) and proteins
  organized into chromosomes
• Genes are 1) part of chromosomes 2) segments of
  DNA

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DNA

• DNA contains genes
• Genes are specific sequences of nucleotide bases
  whose sequences carry information required for
  constructing proteins, which provide the
  structural components for essential biochemical
  reactions (p. 53).
• DNA is made up of two chains of nucleotides that
  wind around each other like a twisted ladder
  whose sides are made up of sugars and
  phosphates (p. 53).

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DNA

• Steps of DNA ladder made up of bonded pairs of
  nitrogenous bases (base pairs)
• They include adenine (A) and thymine (T), as well
  as cytosine (C) and guanine (G)
• Order of these chemicals determines WHAT you are

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Genes

• Human genome contains 30,000 genes
• or 3 billion base pairs
• Genes carry all information organism needs to
  survive and behave, including proteins.

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Genes

• Genes direct synthesis of proteins
• Proteins serve various functions in our bodies
• Proteins are large, complex molecules that play
  many critical roles in the body they are
  required for the structure, function, and
  regulation of the bodys tissues and organs.
• http//ghr.nlm.nih.gov/ghr/picture/proteinSyn

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Genes

• Proteins determine, among other things, how the
  organism looks, how well the body metabolizes
  food or fights infections, how the organism
  looks, and even how it behaves (p. 54).
• So, genes determine WHAT we are

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• Do they determine WHO we are?

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Genes and Behavior

• NO! (see pp. 55-57)
• Genes do NOT determine physical, medical, or
  behavioral conditions
• Genes increase or decrease the likelihood of
  physical, medical, or behavioral conditions
• e.g., cancer, height, ADHD, mental illness

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Genes and Behavior

• Genes thus predispose one to certain conditions
• But environmental conditions matter too!
• Seeds from a prize-wining rose are very likely
  to realize their maximum genetic potential in a
  Virginia garden but are unlikely to thrive at all
  if planted in the Nevada desert (p. 57).
• Genotype X Environment Phenotype (p. 57)

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Genes Play a Role in

• Homosexuality
• Aggression
• Impulsivity
• Nurturing
• Drug abuse
• IQ
• Antisocial personality
• Extroversion
• Anxiety

• Empathy
• Self-control
• Egoism
• Conscientiousness
• Negative emotionality
• Thrill-seeking
• Mental illnesses
• ADHD
• Suicide

How many of these involve criminality
in some way???
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Genes and Criminality

• So, genes are involved in criminality
• But how do we know?
• Family studies, adoption studies, twin studies,
  and molecular genetic studies

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Family studies

• If criminality is affected by genes, crime should
  run in families
• All types of crime run in families
• But, families share genes AND environments

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Adoption studies

• If criminality is affected by genes, adopted
  children should be similar to their biological
  parents
• Adopted children are often more like biological
  parents than adoptive parents
• (concordance rates are higher)

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Twin studies

• If criminality is affected by genes, identical
  twins should be more similar than fraternal twins
• Identical twins come from one egg and sperm (MZ)
  and share 100 of their genes
• Fraternal twins come from two eggs and two sperm
  (DZ) and share about 99.5 of their genes

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Twin studies

• MZ twins are more alike than DZ twins
• Both when raised together and apart
• (concordance rates are higher)

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Molecular genetic studies

• Identify a specific gene and try to determine its
  function(s) examples
• Peg 3/Mest genes good mother genes
• Nr2el gene fierce gene
• D4DR gene thrill-seeking gene
• DAT1 gene externalizing behavior gene
  (chronic aggression, delinquency, and
  destructive, oppositional, and impulsive behavior)

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But keep in mind

• Human behaviors are complex and are thus affected
  by numerous genes (polygenic)
• Effects of genes changes over course of life
• Same with environmental factors