Bio Exp- Genetic

Question 1

Assumptions Genetic explanation for offending

Answer 1

Criminal tendencies can be inherited

Investigation of a persons genetic material, brain or body will reveal criminal tendencies

Stressors in the environment can trigger genetics but people are predisposed to crime (diatheisis stress model)

Question 2

Twin studies

Answer 2

Christiansen 1977
Over 3500 twin pairs in Denmark born between 1880 and 1990 with ‘offender behaviour’ checked against Danish police
Found:
Concordance rate:
35% monozygotic
13% dizygotic
Shows not just behaviour inherited but genetic predisposition aswell

Question 3

Candidate gene MAOA

Answer 3

MAOA:
Gene coding for enzyme that regulates dopamine and serotonin which has role in impulsive aggression

MAOA-L (variation causing low activity this enzyme)

Chambers- Called warrior gene- found more in New Zealand Māori men 56% vs 34% white men

Mutation of X chromosome so affects men mostly because …

Brunner- 28 men from large Dutch crime family involved in repeated impulsive crime. Found had MAOA-L variant

Question 4

Candidate gene CDH13

Answer 4

Linked to substance abuse and ADHD

5-10% of severe violent crime in Finland is attributable to MAOA and CDH13

Question 5

Diathesis stress model

Answer 5

MAOA- Frazzetto
Found higher levels of antisocial aggression and MAOA-L variant in men but only those who had experienced significant trauma before age 15(physical or sexual abuse).
Those with variant but no trauma didn’t show same levels of aggression

Twins- Mednick
-13.5% turned out criminals if niether biological or adopted parents where criminals
-20% if bio parent was
-24% if bio+adopted were
Shows both affect child through nature and nurture but biological apears to have biggest impact with 7% increase

Question 6

Strength genetic (applications)

Answer 6

can Intervene with children in families with these genes- CBT, anger management, can try and prevent them becoming criminals

Question 7

Strength genetic (hollistic)

Answer 7

Diatheisis stress acknowledges both bio and environment, better then atavism, more hollistic

Question 8

Limitation genetic (issues with study)

Answer 8

Issues with twin studies:
Identical twins may be treated more similar than dz twins, (as well as more similar genes)
This may affect behaviour being more similar

Adoptions may take place at later age but child may already have experienced crime by then

Question 9

Adoption study

Answer 9

Crowe:
Adoptees who’s biological mother is criminal has 50% chance of criminal record by 18
Vs control of 5%