RT Journal Article SR Electronic(1) A1 Bottacini, Francesca A1 Medini, Duccio A1 Pavesi, Angelo A1 Turroni, Francesca A1 Foroni, Elena A1 Riley, David A1 Giubellini, Vanessa A1 Tettelin, Hervé A1 van Sinderen, Douwe A1 Ventura, MarcoYR 2010 T1 Comparative genomics of the genus Bifidobacterium JF Microbiology, VO 156 IS 11 SP 3243 OP 3254 DO https://doi.org/10.1099/mic.0.039545-0 PB Microbiology Society, SN 1465-2080, AB Whole-genome sequencing efforts have revolutionized the study of bifidobacterial genetics and physiology. Unfortunately, the sequence of a single genome does not provide information on bifidobacterial genetic diversity and on how genetic variability supports improved adaptation of these bacteria to the environment of the human gastrointestinal tract (GIT). Analysis of nine genomes from bifidobacterial species showed that such genomes display an open pan-genome structure. Mathematical extrapolation of the data indicates that the genome reservoir available to the bifidobacterial pan-genome consists of more than 5000 genes, many of which are uncharacterized, but which are probably important to provide adaptive abilities pertinent to the human GIT. We also define a core bifidobacterial gene set which will undoubtedly provide a new baseline from which one can examine the evolution of bifidobacteria. Phylogenetic investigation performed on a total of 506 orthologues that are common to nine complete bifidobacterial genomes allowed the construction of a Bifidobacterium supertree which is largely concordant with the phylogenetic tree obtained using 16S rRNA genes. Moreover, this supertree provided a more robust phylogenetic resolution than the 16S rRNA gene-based analysis. This comparative study of the genus Bifidobacterium thus presents a foundation for future functional analyses of this important group of GIT bacteria., UL https://www.microbiologyresearch.org/content/journal/micro/10.1099/mic.0.039545-0