Criminology Chapter: DNA and Serological Evidence

Criminology Study Notes

DNA and Serological Evidence

• Definition: DNA (Deoxyribonucleic acid) is a molecule that contains an individual's genetic information. Serological evidence refers to the analysis of bodily fluids such as blood, semen, and saliva.
• Importance in Criminology: DNA and serological evidence are crucial in forensic science, helping investigators identify suspects, link crimes, and exonerate the innocent.
• Types of DNA Evidence:
  • Nuclear DNA (nDNA): found in the nucleus of cells, unique to each individual.
  • Mitochondrial DNA (mtDNA): found in mitochondria, inherited from mother, useful for identifying remains.
• DNA Analysis Techniques:
  • PCR (Polymerase Chain Reaction): amplifies DNA samples.
  • STR (Short Tandem Repeat) analysis: compares DNA profiles.
• Limitations:
  • Contamination risk
  • Degradation of DNA over time
  • Limited DNA samples

Typologies of Sex Offenders

• Definition: Classification of sex offenders based on their motivations, behaviors, and characteristics.
• Types of Sex Offenders:

  Opportunistic Offenders

    + Take advantage of situations, often without planning.
    + May not have a clear motive or preference.
  

  Preferential Offenders

    + Have a specific preference for victims (e.g., children, women).
    + Often plan and prepare their crimes.
  

  Sadistic Offenders

    + Derive pleasure from inflicting pain or humiliation.
    + Often have a history of violent or abusive behavior.
  

  Fixated Offenders

    + Have a persistent and intense attraction to a specific age group or type of victim.
    + May have a history of voyeurism or exhibitionism.
  

  Regressed Offenders

    + Typically older, with a history of sex offenses.
    + May have a paraphilia (e.g., pedophilia, exhibitionism).
  

These typologies are not mutually exclusive, and offenders may exhibit characteristics from multiple categories. Understanding these typologies can aid in crime prevention, investigation, and rehabilitation strategies.

DNA and Serological Evidence

• DNA (Deoxyribonucleic acid) is a molecule that contains an individual's genetic information.
• Serological evidence refers to the analysis of bodily fluids such as blood, semen, and saliva.
• DNA and serological evidence are crucial in forensic science, helping investigators identify suspects, link crimes, and exonerate the innocent.
• There are two types of DNA:
  • Nuclear DNA (nDNA): found in the nucleus of cells, unique to each individual.
  • Mitochondrial DNA (mtDNA): found in mitochondria, inherited from mother, useful for identifying remains.
• DNA analysis techniques include:
  • PCR (Polymerase Chain Reaction): amplifies DNA samples.
  • STR (Short Tandem Repeat) analysis: compares DNA profiles.
• Limitations of DNA evidence include:
  • Contamination risk.
  • Degradation of DNA over time.
  • Limited DNA samples.

Typologies of Sex Offenders

• Typologies of sex offenders involve classification based on motivations, behaviors, and characteristics.
• There are five main types of sex offenders:

Opportunistic Offenders

• Take advantage of situations, often without planning.
• May not have a clear motive or preference.

Preferential Offenders

• Have a specific preference for victims (e.g., children, women).
• Often plan and prepare their crimes.

Sadistic Offenders

• Derive pleasure from inflicting pain or humiliation.
• Often have a history of violent or abusive behavior.

Fixated Offenders

• Have a persistent and intense attraction to a specific age group or type of victim.
• May have a history of voyeurism or exhibitionism.

Regressed Offenders

• Typically older, with a history of sex offenses.
• May have a paraphilia (e.g., pedophilia, exhibitionism).
• These typologies are not mutually exclusive, and offenders may exhibit characteristics from multiple categories.
• Understanding these typologies can aid in crime prevention, investigation, and rehabilitation strategies.