title: Human gut microbiome: the second genome of human body.
abstract: The human body is actually a super-organism that is composed of 10 times more microbial cells than our body cells. Metagenomic study of the human microbiome has demonstrated that there are 3.3 million unique genes in human gut, 150 times more genes than our own genome, and the bacterial diversity analysis showed that about 1000 bacterial species are living in our gut and a majority of them belongs to the divisions of Firmicutes and Bacteriodetes. In addition, most people share a core microbiota that comprises 50-100 bacterial species when the frequency of abundance at phylotype level is not considered, and a core microbiome harboring more than 6000 functional gene groups is present in the majority of human gut surveyed till now. Gut bacteria are not only critical for regulating gut metabolism, but also important for host immune system as revealed by animal studies.
authors.affiliation: CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China. zhubaoli@im.ac.cn
authors.forename: Baoli
authors.initials: B
authors.lastname: Zhu
authors.forename: Xin
authors.initials: X
authors.lastname: Wang
authors.forename: Lanjuan
authors.initials: L
authors.lastname: Li
mesh_terms: D000818:Animals; D058448:Biota; D018929:Cell Culture Techniques; D004064:Digestive System / Q000276:immunology / Q000382:microbiology*; D004066:Digestive System Diseases / Q000382:microbiology; D006801:Humans; D007107:Immune System; D054892:Metagenome; D009765:Obesity / Q000382:microbiology; D013559:Symbiosis