Humans ; Incisor ; Tooth Apex ; abnormalities

Gut microbiome sequencing studies have great potential to translate microbial analysis outcomes into human health research. Sequencing strategies of 16S amplicon and whole-metagenome shotgun (WMS) are two main methods in microbiome research with respective advantages. However, how sample heterogeneity, sequencers and library preparation protocols affect the sequencing reproducibility of gut microbiome needs further investigation. This study aims to provide a reference for the selection of sequencing technologies by comparing differences in microbial composition from different sampling sites. The results of three widely adopted sequencers showed that the technical repetition correlation (r= 0. 94) was high in WMS method, while the biological repetition correlation (r = 0. 69) was low. Bray-Curtis distance identified that dissimilarity from biological replicates was larger than that of technical replicates (P<0. 001). In addition, dissimilarity and specific taxonomic profiles were observed between 16S and WMS datasets. Our results imply that homogenization is a necessary step before sample DNA extraction. The sequencers contributed less to taxonomic variation than the library preparation protocols. We developed an empirical Bayes approach that " borrowed information" in calculations and analyzed batch effect parameters using standardized data and prior distributions of (non-) parameters, which may improve population comparability between 16S and WMS and provide a basis for further application to fusion analysis of published 16S and microbial datasets.