Making microbiomes

In the study of human microbial ecology, microbiota are the microorganisms that make up the ecological communities on the human body, and microbiome refers to the microbial genes in these communities. It is estimated there are at least as many microbial cells in our bodies as human cells, and the number of genes represented in our indigenous microbial communities likely matches our 23,000 Homo sapiens genes with eight million microbial genes. From the biological science point of view, humans are supraorganisms (a system of multiple organisms functioning as one) or holobionts (the singular ecological unit made up of symbiotic assemblages) - composites of human and microbial selves. We have evolved from, and with these microbes. Human microbiomes inextricably entangle biological processes with social practices; microbial populations - affected by how and where we are born, what food we eat, who we live with and love - are digesting our food, training our immune systems, interacting with our states of health and illness, moods, and behavior. This chapter addresses three concerns: how the microbiome is produced as an experimental object in the context of genomic knowledge, what social science approaches to microbiome science have emerged, and how knowledge about microbiota is crucially bound to the highly specific technologies used to sequence microbial genomes.