Can You Predict a Monkey’s Social Status by Looking at Its Genes?

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http://blogs.scientificamerican.com/observations/2012/04/09/can-you-predict-a-monkeys-social-status-by-looking-at-its-genes/



Rhesus macaques, which are some of the best studied of all monkeys, establish hierarchies in their social groups. Whenever two macaques tussle over a piece of food, say, or the right to mate, the monkey with the higher rank usually wins. Primatologists have established that monkeys of a lower social status are generally more stressed out than their dominant peers—low-ranking monkeys have higher levels of stress hormones, for instance. But what about differences in gene activity? Does one’s social stature change how one’s genes are expressed. Yes, concludes a new study that used differences in gene expression to identify a monkey’s social status with around 80 percent accuracy.

Jenny Tung of Duke University and her colleagues—including several collaborators at the Yerkes National Primate Research Center—studied 10 groups of adult female rhesus macaques made up of five females each. Researchers formed the groups one female at a time, which allowed them to carefully construct the social hierarchy: females introduced earlier generally assumed a higher rank. In this way, the scientists knew exactly which monkey held rank 1, 2, 3, 4 and 5 in each group.

Tung and her colleagues collected blood samples from the rhesus macaques, isolated the white blood cells and analyzed the DNA in those cells. They found 987 genes whose activity depended on social rank: 535 genes that were more highly expressed in high-ranking individuals and 452 genes with higher activity in low-ranking individuals. Many of these genes were involved with the immune system; in particular, genes involved in inflammation were more active in low-ranking individuals. Further testing revealed that low-ranking monkeys also had fewer cytotoxic T-cells, a kind of white blood cell that attacks infected and cancerous cells. Earlier research suggests that the stress of a low social rank compromises the immune system—which fits with the finding about T-cells—but may also trigger the immune system to respond when it does not need to, which fits with the finding about inflammation. Findings about the relationship between stress, social status and the immune system are not clear cut, however; for example, some studies have found that having a higher rank is more stressful than having a lower rank.

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1. I remember a study they did on baboons. They gave them antidepressants (SSRIs) to the low

status apes. This caused their status to rise and put the previously high status baboons into a tissy. They got totally stressed out. As a gentle person, who has been on SSRIs for years, I can say they have upped my quality of life. I don't go anywhere near the high status people. I like regular folk. Always have.