Comparative Genomic Analysis of Members of the Genera and Reveals Distinct Clades with Specific Potential Metabolic Functions.

and species represent some of the most prevalent methanogenic archaea in the gastrointestinal tract of animals and humans and play an important role in this environment. The aim of this study was to identify genomic features that are shared or specific for members of each genus with a special emphasis of the analysis on the assimilation of nitrogen and acetate and the utilization of methanol and ethanol for methanogenesis. Here, draft genome sequences of strain DSM 11995, strain DSM 11979, and strain 4103 are reported and compared to those of 16 other and genomes, including genomes of the 13 currently available types of strains of the two genera. The comparative genome analyses indicate that among other genes, the absence of molybdopterin cofactor biosynthesis is conserved in species but reveals also that the three species share a core set of more than 300 genes that distinguishes the genus from the genus . Multilocus sequence analysis shows that the genus can be subdivided into clades, potentially new genera, which may display characteristic specific metabolic features. These features include not only the potential ability of nitrogen fixation and acetate assimilation in a clade comprised of species from the termite gut and strains but also the potential capability to utilize ethanol and methanol in a clade comprising strain DSM 11976, sp. AbM4, and strain DSM 25824.