RESEARCH PAPERS: PDF OnlyPleiotropy of the serotonin transporter gene for seasonality and neuroticismSher, Leoa; Greenberg, Benjamin D.b; Murphy, Dennis L.b; Rosenthal, Norman E.a; Sirota, Lev A.c; Hamer, Dean H.cAuthor Information aSection on Biological Rhythms andbLaboratory of Clinical Sciences, National Institute of Mental Health, Bethesda, Maryland, USA;cLaboratory of Biochemistry, National Cancer Institute, Bethesda, Maryland, USA Correspondence to Leo Sher MD, Department of Neuroscience, New York State Psychiatric Institute, 1051 Riverside Drive, Suite 2917, Box 42, New York, NY 10032, USA. E-mail:[email protected] Received 26 April 2000; accepted 7 September 2000 Psychiatric Genetics: September 2000 - Volume 10 - Issue 3 - p 125-130 Buy Abstract Pleiotropy refers to the ability of a single gene to influence multiple traits. A polymorphism in the regulatory region of the serotonin transporter gene (5-HTTLPR) has previously been found to be associated both with the personality trait of neuroticism and with seasonal changes in mood and behavior, or seasonality. Hypothesizing that the contribution of the serotonin transporter gene to seasonality is specific, i.e. independent of neuroticism, we measured 5-HTTLPR genotypes and both psychological traits in 236 healthy volunteers. The results indicated that the 5-HTTLPR contributions to variation in the two traits are largely independent; approximately three-quarters of the effect of the gene on seasonality are not related to its effects on neuroticism. Moreover, the gene has a larger effect on the covariation between neuroticism and seasonality than it does on either trait alone. Sibling-pair analysis confirmed that the effects of the 5-HTTLPR are due to genetic pleiotropy rather than population stratification. © 2000 Lippincott Williams & Wilkins, Inc.