Abstract # 206:

Scheduled for Saturday, August 20, 2005 08:45 AM-09:00 AM: Session 15 (Parliament Room) Oral Presentation


DEVELOPMENTAL TRAJECTORIES OF FREE-RANGING CAYO SANTIAGO RHESUS MALES: EVIDENCE OF ASSOCIATION WITH A POLYMORPHISM IN THE SEROTONIN TRANSPORTER PROMOTER REGION (SLC6A4)

K. L. Rasmussen Robbins1, A. J. Bennett2, M. L. Laudenslager3 and S. J. Suomi1
1Laboratory of Comparative Ethology, NIH, NIH Animal Center, Bldg. 112, P.0.Box 529, Poolesville, MD 20837, USA, 2Departments of Physiology/Pharmacology, Wake Forest University School of Medicine, 3Department of Psychiatry, University of Colorado Denver and Health Sciences Center
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     The neurotransmitter serotonin 5-hydroxytryptamine (5-HT) plays a major role in regulating processes such as feeding, sleep and reproduction in primates. Variation in allele length in the promoter region of the serotonin transporter gene, SLC6A4, has been shown to influence both behavior and physiological function in humans and those nonhuman primates where it has been examined. We conducted a pilot study with 13 male rhesus (Macaca mulatta) from the free-ranging colony of Cayo Santiago, PR. Each year from birth through 8 years of age the males were captured and their measurements, EKG and cortisol (CORT) levels were obtained. When genotyped, four males were homozygous for the long allele (l/l) and nine were heterozygous, carrying long and short alleles (l/s) in the promoter region. The heterozygous l/s males were larger than l/l males (years 1-8, p<0.01) and showed an earlier growth spurt between the ages of 3-4 years. From years 3-8, l/s males also had significantly larger testes (P < 0.05). In years 2-8, l/s males tended to have lower CORT levels (P = 0.08) and lower heart rates (P = 0.09). Since heterozygous l/s males had larger body and testis size than l/l males and the CORT and EKG data tentatively suggest that l/s males were less reactive, heterozygous l/s males might potentially have a competitive and reproductive advantage over their l/l counterparts.