If a monkey's social status changes, her immune system changes along with it. Scientists studying rhesus macaques at Emory's Yerkes National Primate Research Center say they can predict a rhesus macaque's rank within a small group by examining gene expression levels in her immune cells.
This finding may have implications for how the stress of low socioeconomic status affects human health and how individuals' bodies adapt after a shift in their social environment. The results are published this week in the Proceedings of the National Academy of Sciences Early Edition.
The lead author of the study is Jenny Tung, who is now assistant professor of evolutionary anthropology at Duke University.
Primate researchers can tell macaques' social rank by watching them engage in competitive interactions, such as grooming and accessing food and water. Tung and her colleagues studied 10 groups of female macaques (five each) in which researchers could manipulate individuals' social rank. Before being placed into new groups, all of the macaques started out as middle rank.
"In the wild, macaques inherit their social rank from their mothers" Tung says. "But in our research, the order of introduction determines rank; the newcomer is generally lower status. When some macaques' status changed after a newcomer arrived, so did their patterns of immune system gene activity."
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