Abstract # 32:

Scheduled for Thursday, June 19, 2008 05:00 PM-07:00 PM: Session 4 (Ball Rooms A and B) Poster Presentation


K. Herman1,2, M. Schwandt3, A. Ruggiero1, C. S. Barr3 and S. J. Suomi1
1Laboratory for Comparative Ethology, NIH Animal Center, P.O. Box 529, Poolesville, MD 20842, USA, 2Child Development Laboratory, University of Maryland, 3Primate Unit, Laboratory of Clinical Studies, Division of Intramural Clinical and Biological Research, National Institute on Alcohol Abuse and Alcoholism
     Human studies indicate that early experience modifies the impact of genes on the development of social competence. Similar gene-environment interactions appear to influence social development in rhesus macaques (Macaca mulatta). As in humans, the rhesus macaque genotype contains bi-allelic length variation (long (l) versus short (s)) in the serotonin transporter promoter region (rh5-HTTLPR) which contributes respectively to high versus low serotonin transporter transcription rates. In the present study, we investigated the stability of fear-related behavior in macaque infants (n=339) across multiple time points during the first five weeks after birth, using data from the Primate Neonatal Neurobehavioral Assessment. Subjects were reared with mothers and peers or by human caretakers in our nursery, and were either homozygous dominant (l/l) or heterozygous (l/s) at the rh5-HTTLPR. A repeated measures ANOVA revealed an interaction between rearing and genotype on the frequency of fear grimaces [F(1,336)=4.95; p=0.03]. Mother-reared l/s infants were less fearful than l/l infants, while nursery-reared l/s subjects were more fearful than l/l subjects. Across the first month, nursery-reared subjects became more fearful while mother-reared subjects became less fearful [ANOVA, F(3,1008)=9.68; p=0.0001]. In sum, l/s infants appear to be more sensitive to adverse and normative/supportive rearing experiences. These findings hint at a possible evolutionary explanation for the maintenance of the short allele within rhesus macaque populations.