Candidate genes personality DRD4 Flashcards
Link between DRD4.7 and promiscuity
- Questionnaires, US students.
- Those with 7 or more repeats had almost 2x greater promiscuity rate and were more likely to be unfaithful during a committed relationship
Garcia et al 2010
Link between DRD4 polymorphism, sexual desire, arousal and function.
- NB subjects were volunteers: recruited by an advertisement on an internet site for subjects who had already given DNA in previous studies. However efforts were made to keep process anonymous and avoid direct contact: recruited by phone, gave no details apart from an identifying code, online questionnaire.
- Used online questionnaire on sexual desire, arousal and function.
- 5 polymorphisms were genotyped in 148 subjects.
- Men and women differed significantly on desire and function scores.
- DRD4 exon 3 most common D4.4 repeat was negatively associated with desire. D4.7 carriers showed higher sexual function/desire than D4.4
- C-521 ‘T’ alleles also showed higher desire scores,
Zion et al 2006
Interaction with high number of friends leads to liberal politics?
- 2574 subjects. Comparison within families to avoid stratification
- Those with DRD4-7R and a large number of friends are more likely to be liberal in their policies.
Settle et al 2010
Effects in different directions for men and women for cognitive empathy (‘I try to look at everybody’s side of the disagreement before I make a decision’)
- DRD4-7R associated with higher cognitive empathy in females, but lower cognitive empathy in males.
Uzefovsky et al 2014
124 subjects
7-repeat allele was significantly associated with Cloniger’s trait of ‘Novelty Seeking’
NB results have not always been replicated
Ebstein et al 1996
DRD4 gene may be associated with measures of novelty seeking and impulsivity (but not extraversion). The association of C-521T variant with these measures, if genuine, may account for up to 3% of phenotypic variance.
Meta-analysis of studies of the association between DRD4 gene variable number of tandem repeats (VNTR) and C-521T polymoprphisms and human approach-related personality traits, including novelty seeking, extraversion and impulsivity.
- Adult samples from nonpsychiatric populations.
- Then extended on this literature by trying to confirm any evidence of association in a replication sample (n-309) selected for extreme scores on the extraversion subscale of the Eysenck Pesrsonality Questionnaire from a large (n~40000) population based samples)
Results:
- Initial meta-analysis supported association of DRD4 C-521T polymorphism but not the VNTR polymorphism, with approach-related traits.
- Conclusion was qualified by evidence of signidicant publication bias & failure to detect assocaiation in a replication sample comprising individuals at the extremes of the trait distribution.
- Association of C-521T polymorphism was robust to inclusion of these new data, but revised meta-analysis indicated that association was present for novelty seeking and impulsivity but not extraversion.
Munafo et al 2008
In unselected wild caught birds, SNP830 polymorphism correlates with novelty-seeking.
- Studies wild-caught great tits, a species in which selective breeding has previously shown that novelty-seeking has a significant genetic basis. Measured (a) exploration in a novel environment and (b) birds reaction to 2 different novel objects placed in home cage
- Composite score for (a) and (b) was related to an SNP at position 830 of the DNDR4 nucleotide sequences.
- BUT NB awkward issue with this polymorphism: substitution of C to T is ‘synonymous’ as both cases encode alanine. Possible alternative differencially affect transcription, splicing or the stability of RNA? Or might be in linkage disequilibrium with another polymorphism nearby.
Fidler et al 2007
