Fig. 1.

Number of gut microbiome studies across different host clades, and whether a study was comparative or not. Studies were collected in September 2023 using the Scopus document search tool. We counted only published journal articles and excluded all other article types (including reviews). The top row includes studies with human subjects and laboratory animals (w/ humans & lab animals) while the bottom row does not include these studies (w/o humans or lab animals). Both 16S and metagenomic studies are included.