Can Microbes Give Gifts?

I find it ironic that theory, which is the epitome of cooperation and togetherness, can deeply divide people who spend their entire time thinking about cooperation and togetherness.

– Ed Yong, I Contain Multitudes

Shortly after I finished reading I Contain Multitudes, I attended an interdisciplinary meeting of microbiome ecologists, evolutionary biologists, and social scientists. Topics of discussion included human-microbial coevolution; the role microbiota might play in preventing obesity; and the use of microbes to understand health in the ancient world.  

Over and over again, though, the conversation turned back to the issue of common ground. What kind of theory might make social and natural scientists cooperate?

Searching for such common ground, one anthropologist at the table asked the scientists, “Do microbes give gifts?” 

We couldn’t come up with a satisfying interdisciplinary answer to this question, but I couldn’t stop thinking about it.  I took a look back at I Contain Multitudes looking for cluesI realized that while Ed Yong’s book may look like a story about scientists and the microbes they love, it could also be read as a story about exchange. I think that it may be through exchange that anthropologists and natural scientists can find a common way of speaking about the microbiome.

Many of the stories Yong tells are about the “partnerships” microbes form with one another and with their plant and animal hosts. These trans-species partners exchange genetic material, collaborate on metabolic functions, digest each other’s waste, and work together to keep a common ecosystem stable. Yong even (if maybe unwittingly) trots out some anthropological jargon when he tells us that, “an evolutionary partnership could easily be seen as reciprocal exploitation” (my emphasis). Sometimes, each partner gets something out of the other, but over time, one partner may take too much.

Sounds familiar. As we teach our introductory anthropology students when we introduce the concept of gift exchange, reciprocity is always unstable. It’s ridden with potential for conflict and breakdown. “There’s no such thing as a free gift,” as we like to say. If the conditions aren’t right, any exchange relationship can deteriorate. The microbes that protect me from infection today might, under different environmental conditions, make me sick tomorrow. Anthropologists also know that exchange networks are dense. The “spirit of the gift” isn’t just about a two-way relationship between friends, but about kinship, political organization, and even our relationships to our ancestors. What I learned from Yong’s book is that partnerships with and among microbes are not so different. My relationship with one microbe depends for its stability on that microbe’s relationship with other microbes, and other people.

As Yong explains, the key question in all these symbiotic economies is, “how can the selfish interests of individuals be overcome to form cooperative groups?”

For most anthropologists, of course, the basis of exchange is not self interest but obligation. One’s impulse to give or receive—even one’s willingness to cheat or deceive a trading partner—is always social. For us, the germ of economic behavior is not the unitary self, but the connected self.  

But I think that Yong, in his own way, gets this when he writes that the way to “seal a symbiosis” is through “inheritance.”

“Animals,” Yong tells us, “are driven to evolve ever more efficient ways of passing their heirlooms to their offspring.” The “heirlooms” here are beneficial traits, such as the ability to synthesize a particular protein. Those traits are beneficial, says Yong, so long as they keep one species entangled in partnership with others.  

Anthropologists see inheritance in much the same way. Inheritance is not just about holding onto things. It’s also about holding on to relationships, moving them forward in time.

As Yong explains, inheritance in the microbial economy happens at many levels. Not only do microbes pass “heirlooms” on to their offspring that allow them to live well together with others, host organisms—including humans—pass entire communities of microbes onto their offspring. The community of microbes I inherited from my mother influences how I end up interacting with other animals, plants, and people—my allergies, my tolerances, maybe even the shape and size of my body.

Should it be any wonder, then, that so many of the scientists Yong meets seem consumed by the ethical dilemmas of kinship?

Consider two stories told by Yong’s interlocutors. According to microbiome scientist and author Martin Blaser, the overuse of antibiotics and other antimicrobial chemicals is producing new epidemics of obesity and autoimmune disorders, and maybe even some cancers. We are leaving our descendants microbially poorer—not richer—and disease is the result. Scientist Rob Knight tells the story of the dilemma he faced when his daughter came down with a Staphylococcus infection. In a conversation with Yong, Knight ponders how giving her antibiotics might alleviate her pain in the short term, but make her “one BMI fatter” by age eight.

The stories Yong hears from Knight and Blaser are understandable from an anthropological viewpoint. These guys aren’t just scientists, after all. They’re consumers caught up in an industrial capitalist food system run on antibiotics. They’re parents who are no less sensitive to fat-shaming than any of the rest of us. For them, to adopt Bruno Latour’s terms, the microbiome is not so much “a matter of fact” as it is “a matter of concern.” Walt Whitman notwithstanding, microbial partnerships are about an indeterminate “we,” not an unified “I.”

So even though Yong spends a lot of time talking about the importance of “self interest,” his book also shows us something else. Life in the world we’ve created in partnership with microbes is mostly about obligation, specifically the obligation to give and receive “gifts.” In anthropology, this obligation precedes individual self interest.

If Yong’s project has a mission, it is to point his readers to what another of his scientist-informants calls “the beauty of biology,” namely, the insight that “We are social creatures [who] seek to understand our connections to other living entities.”  

That is also the beauty of anthropology.

Alex Nading is a Lecturer in Social Anthropology at the University of Edinburgh.