WIKIMEDIA, MATTOSAURUSAn expanded catalog of nearly 9.8 million genes from the human gut microbiome spans a cohort of bacteria three times larger than that used to create previous gene lists. The results, published this week (July 6) in Nature Biotechnology, integrate data from newly sequenced samples and previous studies to provide near-complete gene sets for most gut microbes.
Led by a team from BGI in Shenzhen, China, the researchers sequenced 249 new fecal samples taken from adults in Denmark and Spain. They also used 1,018 published samples from the Human Microbiome Project, MetaHIT, a large diabetes study in China, and more than 500 sequenced genomes of gut microbes. Most of the microbes identified in these latest samples were known to occur in the human gut. But the authors found 13.5 percent of the current cohort also carried Oenococcus, a bacterium used in wine fermentation that has not been previously found in the gut microbiome.
The study also found country-specific differences in gut microbes from healthy Danish and Chinese adults. The two groups had significant differences in the types of microbial genes for nutrient metabolism and detoxification of foreign substances. The researchers also found differences in genes potentially linked to antibiotic resistance, with penicillin resistance more prevalent in the Dane population and multi-drug resistance more common among Chinese participants.
The authors estimate that the integrated gene catalog spans 94.5 percent of genes discovered in the gut microbiome so far. Catalogs such as this help researchers quantitate and characterize the gut microbiome to “understand its variation across populations in human health and disease,” study author Junhua Li of BGI said in a statement.