Genetic and neural explanations (A01)

Genetic explanations-

This explanation suggests that offenders inherit a gene, or a combination of genes, which predispose them to commit crime.

• Twin studies are used to support this explanation. Lange investigated 13 identical (MZ) and 17 non-identical (DZ) twins where one of the twins in each pair had been in prison. He found that 10 of the MZ twins but only 2 of the DZ twins had a co-twin who had also been in prison. More recently, Christiansen studied 87 MZ and 147 DZ twins and found a concordance of 33% for MZ twins and 12% for DZ twins. 
• Candidate genes- Tiihonen et al carried out a genetic analysis of almost 900 offenders which revealed abnormalities on two genes that may be associated with genetic behaviour. The MAOA gene (which controls dopamine and serotonin in the brain and has been linked to aggressive behaviour)…