16S rRNA Metagenomics of Asian Gut Microbiota

To characterize the diversity of gut microbial community structures of Asian people, Asian Microbiome Project (AMP) has been established. AMP notably aims to understand the linkage of their gut microbiota with diets and its impact on their health. To that end, AMP began with phase I which focused on the gut microbiota of school-age children who must follow the regional dietary habit. Stool samples were collected from 303 school-age children living in urban or rural regions in five countries spanning temperate and tropical areas of Asia. Bacterial compositions of those samples were determined by using the hypervariable sequences of 16S rRNA V6-V8 region analyzed by 454 pyrosequencing platform. Their community profiles were characterized into two enterotype-like clusters, each driven by Prevotella (P-type) or Bifidobacterium/Bacteroides (BB-type), respectively. Moreover, random forest analysis marked the participant country of residence through fecal species analysis by demonstrating accumulating gut microbiota. The predicted metagenomics using PICRUSt program has suggested overrepresentation of certain enzymes which may reflect their intestinal environment, such as amylase for nondigestible starch in P-type subjects and choloylglycine hydrolase for bile acid metabolism in BB-type subjects. Following this pilot study using 454 sequencing platform, MiSeq pair-end sequencing platform has been introduced into AMP. The MiSeq platform covered more than 99% of gut microbial community profile. Enterotyping was reproduced regardless of the read regions and taxonomy levels. Further study using the MiSeq 16S rRNA metagenomics is promising to gain deep insight of gut microbial community of Asian people.