Graduation Year


Document Type

Campus Only Senior Thesis


W.M. Keck Science Department

Second Department


Reader 1

Emily Wiley

Reader 2

Bryan Thines

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© 2014 Sarah E. K. Loebner


Epigenetics is the field of focus when determining how environmental and behavioral factors can directly impact the expression of genes that affect our behavior. Existing studies have examined links between eliciting stress behaviors in pregnant mice and the negative stress behavioral responses in offspring for several subsequent generations, which points to a disposition to adverse stress responses later in life due to early-life epigenetic modifi- cations. Similarly, research on both rats and humans has found early life trauma to be a large factor in both the hyper- and de-methylation of genes responsible for stress processing, which can be linked to depressive behav- ior later in life. The proposed study aims to address the lack of attention to positive psychology in this field of study by seeking to identify epigenetic markers such as hyper- or de-methylation in regions of the rat genome con- taining homologous genes to those in humans potentially linked to positive affect or life satisfaction. Rat offspring reared with either high or low levels of maternal care would be exposed to a novel stressful environment, and a microarray analysis would be performed to assess the differences in gene expression in the previously noted regions of the genome. Gene expression analysis may reveal that offspring who received more maternal care show increased expression of the serotonin transporter gene, down-regulation of genes for proinflammatory cytokines, and up-regulation of anti-viral re- sponse genes. These results would be consistent with the gene expression patterns previously seen in individuals with higher levels of life satisfac- tion, eudemonic pleasure, and optimism.

This thesis is restricted to the Claremont Colleges current faculty, students, and staff.