Comparative metagenomics revealed commonly enriched gene sets in human gut microbiomes.
Numerous microbes inhabit the human intestine, many of which are uncharacterized or uncultivable. They form a complex microbial community that deeply affects human physiology. To identify the genomic features common to all human gut microbiomes as well as those variable among them, we performed a large-scale comparative metagenomic analysis of fecal samples from 13 healthy individuals of various ages, including unweaned infants. We found that, while the gut microbiota from unweaned infants were simple and showed a high inter-individual variation in taxonomic and gene composition, those from adults and weaned children were more complex but showed a high functional uniformity regardless of age or sex. In searching for the genes over-represented in gut microbiomes, we identified 237 gene families commonly enriched in adult-type and 136 families in infant-type microbiomes, with a small overlap. An analysis of their predicted functions revealed various strategies employed by each type of microbiota to adapt to its intestinal environment, suggesting that these gene sets encode the core functions of adult and infant-type gut microbiota. By analysing the orphan genes, 647 new gene families were identified to be exclusively present in human intestinal microbiomes. In addition, we discovered a conjugative transposon family explosively amplified in human gut microbiomes, which strongly suggests that the intestine is a 'hot spot' for horizontal gene transfer between microbes.
Kurokawa
Ken
K
Laboratory of Comparative Genomics, Graduate School of Information Science, Nara Institute of Science and Technology, Ikoma, Nara, Japan.
Itoh
Takehiko
T
Kuwahara
Tomomi
T
Oshima
Kenshiro
K
Toh
Hidehiro
H
Toyoda
Atsushi
A
Takami
Hideto
H
Morita
Hidetoshi
H
Sharma
Vineet K
VK
Srivastava
Tulika P
TP
Taylor
Todd D
TD
Noguchi
Hideki
H
Mori
Hiroshi
H
Ogura
Yoshitoshi
Y
Ehrlich
Dusko S
DS
Itoh
Kikuji
K
Takagi
Toshihisa
T
Sakaki
Yoshiyuki
Y
Hayashi
Tetsuya
T
Hattori
Masahira
M
D000328:Adult; D002675:Child, Preschool; D016000:Cluster Analysis; D005260:Female; D041981:Gastrointestinal Tract / Q000378:metabolism* / Q000382:microbiology*; D005798:Genes, Bacterial; D023281:Genomics; D006801:Humans; D007223:Infant; D007422:Intestines; D008297:Male; D054892:Metagenome / Q000235:genetics*; D008875:Middle Aged; D010802:Phylogeny; D017422:Sequence Analysis, DNA