The term “gnotobiotic” stems from the Greek words “gnosis” (“known”) and “bios” (“life”). Somewhat paradoxically, a gnotobiotic animal is, at least originally, one with no known life. That is, a gnotobiotic animal is born and reared in a sterile environment, so that it is germ free (or GF, in the parlance of the articles I’ve been reading of late). Gnotobiotic animals can be colonized, then, with defined microbiota and used in research that examines the role of specific microbes (e.g., by comparing physiologic processes in gnotobiotic and colonized animals).
Why is this interesting to a sociologist (beyond the opportunity for wordplay with the Rumsfeldian title of the previous post?). Well, it’s interesting to this sociologist because research using gnotobiotic animals is part of recent scientific endeavors, like the Human Microbiome Project (HMP), which focus on the relationship between humans and our microbiota, the microorganisms that live on and in human beings. While many aspects of the HMP are fascinating, I am most riveted by the proposition that it will support an understanding of the human as a “superorganism”:
“If humans are thought of as a composite of microbial and human cells, the human genetic landscape as an aggregate of the genes in the human genome and the microbiome, and human metabolic features as a blend of human and microbial traits, then the picture that emerges is one of a human ‘superorganism'” (Turnbaugh, et al. 18 October 2007. Nature 449: 804).
The argument being made – fairly explicitly – by some scientists is for an “extension” of our view of the self (where self = genotype + phenotype) to include our microbial symbiants, either as part of the self or as a microbial self.
Additional bases for sociological intrigue: 1) There is evidence from mouse models of maternal transmission of microbiota over several generations (“her bacteroides are just like her mother’s!”); 2) The array of traits and outcomes that scientists speculate may be shaped by human-microbiome interactions include not only metabolism, immune function, and organ development, but also dimensions of human psychology and behavior (“you know how guys with AFS519 can be…”); 3) Because microbial symbiants in our guts perform specific functions (e.g., synthesis of otherwise indigestible components of our diets), humans have not independently evolved these capacities (“I wouldn’t be the man I am without my microflora”).
On a practical note: There’s a very recent RFA for folks who are interested in studying the ethical, legal, and social implications of the HMP: