So reports Reuters on a study of gene expression in lonely versus non-lonely people:
All 22,000 human genes were studied and compared, and 209 stood out in the loneliest people.
"These 200 genes weren't sort of a random mishmash of genes. They were part of a highly suspicious conspiracy of genes. A big fraction of them seemed to be involved in the basic immune response to tissue damage," Cole said.
I love that: "a highly suspicious conspiracy of genes!" I guess if the genes are there responding to loneliness with greater inflammatory responses, you could call that a conspiracy. They seem likely to link to social hierarchy, with the sort of relationships studied by Robert Sapolsky in baboons. What the article doesn't give (and I'll wait to see if the research indicates) is whether there may be keystone genes that up- or down-regulate this network. From Sapolsky's work, it seems likely that both stress hormones (cortisol) and social hormones, like oxytocin and vasopressin, may play central roles.
These gene chip studies are very quickly going to get more interesting. We'll see both expression and allelic associations for a lot of unexpected things.