The ranking of a monkey within its social environment and the stress accompanying that status dramatically alters the expression of nearly 1,000 genes, said a study published online on Monday in the Proceedings of the National Academy of Sciences.

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.