PICRUSt Functional Predictive Analysis

According to the full-length 16S rRNA gene sequence of the intestinal microbes, the gene function spectrum of their common ancestors was inferred. The gene function spectra of other unmeasured species in the Greengenes 16S rRNA gene full-length sequence database were inferred to construct a gene function prediction spectra of the entire lineage of archaea and bacteria. The 16S rRNA gene sequence data obtained by sequencing were compared with the Greengenes database, and the “nearest neighbor of the reference sequence” of each sequencing sequence was searched and classified as the reference OTU. According to the rRNA gene copy number of “the nearest neighbor of the reference sequence,” the obtained OTU abundance matrix was corrected. Finally, the microbiota composition data were “mapped” to the known gene function spectrum database to predict the metabolic function of the microbiota (39).