The ranking of a monkey within her social environment and the stress accompanying that status dramatically alters the expression of nearly 1,000 genes, a new scientific study reports. The research is the first to demonstrate a link between social status and genetic regulation in primates on a genome-wide scale, revealing a strong, plastic link between social environment and biology. In a comparison of high-ranking rhesus macaque females with their low-ranking companions, researchers discovered significant differences in the expression of genes involved in the immune response and other functions. When a female's rank improved, her gene expression also changed within a few weeks, suggesting that social forces can rapidly influence genetic regulation.
"We were able to use gene expression to classify individuals based on their rank," said Yoav Gilad, PhD, associate professor of human genetics at the University of Chicago Biological Sciences and senior author of the study in PNAS. "Demonstrating these very plastic and temporal changes was novel and quite interesting."
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Comparing 49 different female monkeys of different rank revealed significant changes in the expression of 987 genes, including 112 genes associated with immune system function. The result fits with data in monkeys where low rank and chronic stress lead to compromised immune function, and, more loosely, with human studies linking low socioeconomic status and high social stress to elevated disease risk.
The overall genetic "signature" of expression changes was robust enough that researchers could predict an individual monkey's social rank with high accuracy from their gene expression profile alone. That predictive power also enabled an unanticipated second test of whether gene expression would reflect unplanned changes in dominance rank.