Mechanism: functional polymorphism in the promotor region of the serotonin receptor gene (-G1438A). The two variants (rs6311 and rs6313) are in complete LD. Each C allele of rs6311 is shown to be associated with lower mRNA and lower protein expression than the T variant (R).
The C-allele has been linked to leadership/social dominance, and predicted greater speed-dating success for men. In contrast, women who carried this C-allele were more likely to be given the cold shoulder by men. [R].
The C-allele was identified as a secret ingredient for popularity among peers [R].
Carrying the C-allele enhanced the relation between aggression and popularity, particularly for those boys who have many female friends [R].
This seems to be an "enhancer" effect of the C-allele whereby popularity relevant characteristics are made more noticeable. There is no "popularity gene", as the C-allele by itself had no effect on popularity [R].
It is significantly associated with Depression.
Individuals carrying haplotypes with minor allele ''T'' experience greater depressive symptoms [R].
CC-homozygotes reported more anger (p=0.004) and aggression-related behavior (p=0.011) [R].
Children homozygous for the ''T'' allele had significantly more severe depression symptoms than those with C/T or T/T genotypes (P=0.025).
The ''T'' allele was associated with Chronic fatigue syndrome (CFS) [R].
''C'' allele was associated with a risk for Rheumatoid arthritis (RA) [R].
''T'' allele was associated with increased risk for irritable bowel syndrome [R].