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A2 Science In Society 3.2
Teacher Notes
Introduction
This activity is similar in style to some of the Unit 3 exam questions.
Research published in 2008 suggested that genetic factors may influence some young men to seek out
friendships with ‘anti-social’ peers. In a longitudinal cohort study of adolescent health, an allele of the
DAT1 gene, known as 10-R, was shown to have an association with young men’s affiliation for
delinquent friends. Having anti-social friends is known to increase the likelihood that an individual will
behave in an anti-social manner.
DAT1 is responsible for the transportation of the neurotransmitter, dopamine. Dopamine is commonly
associated with the brain’s reward system and is released in response to pleasurable experiences such
as those generated by food, sex and social interaction. Once the dopamine signal has been sent, the
protein produced by the DAT1 gene mops up the dopamine and recycles it for use during the next
‘pleasure reward experience’
Suggested answers
(a) What is meant by the term
(i) allele
Alleles are different forms of the same gene which arise from variations in the DNA code
(ii) neurotransmitter.
a chemical that transmits the signal across the junction between two neurons (synapse).
(2 marks)
(b) (i) What is meant by the term ‘longitudinal cohort study’
 random cohort from the general population of interest
 before symptoms appear
 data collected over a period of time
 on symptoms and possible risk factors
 look for correlations between risk factors and symptoms
(HSW Bg)
(3 marks)
(ii) What is the advantage of this type of study compared with other ways of investigating
the hypothesis that the 10-R DAT1 allele is associated with young men’s choice of friendships?
 case control study is other main design
 cohort less risk of bias in selection of cases and controls
 cohort does not rely on memory of past exposure for data on risk factors
(HSW Bg, Bh)
(2 marks)
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A2 Science In Society 3.2
Teacher Notes
(c) Figure 1 shows results from the 2008 study. The correlation scores are indicators of the relationship
between a ‘delinquent peers’ score and three other variables: the presence of DAT1 10-R alleles, the
age of the young male and whether the adolescent’s father had been convicted of a criminal offence.
The correlations marked by an asterisk are said to be statistically significant at a 5 % level, p≤ 0.05.
Figure 1 Effect of the dopamine transporter (DAT1) gene on delinquent peers by risk classification for
male adolescents (N=814)
Correlation scores
Low-risk family
High-risk family
DAT1, 10-R alleles
0.07
0.15*
Age
0.32*
0.24*
Criminal father
0.00
0.03
* significant at 0.05
Adapted from Beaver, Wright, & DeLisi, The Journal of Genetic Psychology, 2008, 169(3), 227–244
(i) Why does it make sense to analyse data separately for young men from high and low risk family
environments, even though the research is about the effects of genes?
• People’s behaviour is shaped by their genes and by factors in their environment
• The more genes involved in a characteristic, the more it can be affected by environmental
influence
• a high risk family environment would be one where there is lack of parental affection or
engagement
(2 marks)
(ii) Does having a father who is a criminal have an impact on the likelihood that a young male
adolescent would have delinquent friends? Refer to Figure 1 to explain your answer.
The correlation scores of 0.00 and 0.03 are very low and suggest that there is no link (HSW Bb)
(1 mark)
(d) Some newspapers reported that a gene for anti-social behaviour had been identified. Do the results
of the research study support this idea or not? Explain your answer.
 The study shows that possessing a specific variant of a gene increases the likelihood of affiliation
with delinquent individuals
 but only in the environment of a high risk family/ correlation not significant in low risk family
 The ‘gene for’ is an allele that affects dopamine transport not specific behaviour
 so even though the gene may lead to behavioural differences, it is not ‘for’ or ‘against’ a
behaviour
 the research only shows that there is an increased risk of associating with delinquent youths we
do not know whether this leads to other forms of anti-social behaviour
 a large sample and longitudinal cohort study suggests reliability
 But fairly weak correlation at 0.15
(HSW Bc, Be)
(4 marks)
(e) Suppose a local education authority decides that, as part of its improving behaviour programme, it
wishes to screen all eleven year old boys to see which version of the DAT1 gene each boy has. The
authority argues that it is trying to identify those at risk of developing friendships with ‘antisocial’
classmates and to ensure that the boys can be monitored.
Page 2
©The Nuffield Foundation, 2009
Copies may be made for UK in schools and colleges
A2 Science In Society 3.2
Teacher Notes
(i) Why might knowledge of the boys’ genotype be a poor basis for improving behaviour?





Genes do not necessarily indicate that the boy will be badly behaved since the results of a
correlational study present average, not individual data (risk and probability)
Home environment determines whether allele has any effect
only one study
weak correlation
The contribution of an identified gene variant to anti-social behaviour in schools may be small in
comparison to other social factors or other genes.
(3 marks)
(ii) Identify any ethical concerns that a scheme of this type may raise
 Labelling of otherwise well behaved young men (medicalisation)
 on basis of quite weak evidence
 Issues of consent for taking DNA samples
 Privacy & confidentiality
(HSW Hj)
(2 marks)
Total 19 marks
Nature and nurture activities developed and written by Nowgen as part of the Wellcome Trust funded Nowgen
School Genomics Project.
August 2009
Page 3
©The Nuffield Foundation, 2009
Copies may be made for UK in schools and colleges
A2 Science In Society 3.2
Student sheets
Introduction
Research published in 2008 suggested that genetic factors may influence some young men to seek out
friendships with ‘anti-social’ peers. In a longitudinal cohort study of adolescent health, an allele of the
DAT1 gene, known as 10-R, was shown to have an association with young men’s affiliation for
delinquent friends. Having anti-social friends is known to increase the likelihood that an individual will
behave in an anti-social manner.
DAT1 is responsible for the transportation of the neurotransmitter, dopamine. Dopamine is commonly
associated with the brain’s reward system and is released in response to pleasurable experiences such
as those generated by food, sex and social interaction. Once the dopamine signal has been sent, the
protein produced by the DAT1 gene mops up the dopamine and recycles it for use during the next
‘pleasure reward experience’
(a) What is meant by the terms
(i) allele
(ii) neurotransmitter.
(2 marks)
(b) (i) What is meant by the term ‘longitudinal cohort study’
(3 marks)
(ii) What is the advantage of this type of study compared with other ways of investigating
the hypothesis that the 10-R DAT1 allele is associated with young men’s choice of friendships?
(2 marks)
(c) Figure 1 shows results from the 2008 study. The correlation scores are indicators of the relationship
between a ‘delinquent peers’ score and three other variables: the presence of DAT1 10-R alleles, the
age of the young male and whether the adolescent’s father had been convicted of a criminal offence.
The correlations marked by an asterisk are said to be statistically significant at a 5 % level, p≤ 0.05.
Figure 1 Effect of the dopamine transporter (DAT1) gene on delinquent peers by risk classification for
male adolescents (N=814)
Correlation scores
Low-risk family
High-risk family
DAT1, 10-R alleles
0.07
0.15*
Age
0.32*
0.24*
Criminal father
0.00
0.03
* significant at 0.05
Adapted from Beaver, Wright, & DeLisi, The Journal of Genetic Psychology, 2008, 169(3), 227–244
Page 1
©The Nuffield Foundation, 2009
Copies may be made for UK in schools and colleges
A2 Science In Society 3.2
Student sheets
(i) Why does it make sense to analyse data separately for young men from high and low risk family
environments, even though the research is about the effects of genes?
(2 marks)
(ii) Does having a father who is a criminal have an impact on the likelihood that a young male
adolescent would have delinquent friends? Refer to Figure 1 to explain your answer.
(1 mark)
(d) Some newspapers reported that a gene for anti-social behaviour had been identified. Do the results
of the research study support this idea or not? Explain your answer.
(4 marks)
(e) Suppose a local education authority decides that, as part of its “Improving Behaviour Programme”, it
wishes to screen all eleven year old boys to see which version of the DAT1 gene each boy has. The
authority argues that it is trying to identify those at risk of developing friendships with ‘antisocial’
classmates and to ensure that the boys can be monitored.
(i) Why might knowledge of the boys’ genotype be a poor basis for improving behaviour?
(3 marks)
(ii) Identify any ethical concerns that a scheme of this type may raise
(2 marks)
Total 19 marks
Page 2
©The Nuffield Foundation, 2009
Copies may be made for UK in schools and colleges