Order the steps in characterizing the healthy human microbiome from initial data collection to analysis.

First, collect samples from healthy people—using sterile swabs for skin or stool kits for the gut—while keeping them cold to preserve DNA. Next, extract the microbial DNA and sequence it, usually with 16S rRNA gene sequencing, to read the bacterial fingerprints. Then, clean the raw reads, group them into operational taxonomic units, and match each group to known bacteria to see who is present. After that, calculate diversity measures and compare groups, such as noting that the gut has higher diversity than skin. Finally, interpret the findings to define what a healthy microbiome looks like, for example seeing that Bacteroides and Firmicutes dominate the healthy gut.