genes

• intro

  2/+ polygenic genes predispose people to CB

  specifically 2 candidate genes especially linked to CB

  Raine twin study (93)

  reviewed research on delinquent behaviour of Mz and Dz twins

  52% concordance rate for delinquency in Mz twins compared to 21% in Dz
• MAOA - warrior gene

  produces MAOA enzyme > breaks down excess serotonin in synapse

  defective = abnormal levels of MAOA enzyme > abnormal serotonin levels = unregulated mood and possible CB
• MAOA - Study

  Hans Brunner et al (93)

  analysed DNA of 28 male members of Dutch family

  history of impulsive and violent crimes (rape and murder)

  all shared particular variant of MAOA gene that led > abnormally low levels of MAOA enzyme
• MAOA - low activity gene extension

  MAOA-L

  abnormally low levels of MAOA enzyme > abnormally low levels of serotonin (stabilises mood and calms anger) > difficulty controlling emotions
• CDH13

  involved in communications between brain cells and linked to controlling impulsive behaviours

  defective = found alongside defective MAOA > poor brain communication and difficulty regulating behaviour