Tools to explore functional changes in the microbiome are limited. Here, we report the complete genome sequence of a strain of Escherichia coli that was isolated from murine stool. This sequence will provide essential information to further develop this tool, and similar tools, to explore the complex murine microbiome.

The laboratory mouse gut microbiome has been extensively studied, but our understanding of its diversity remains incomplete. We report the assembly of 51 draft metagenome-assembled genomes (MAGs) from murine fecal samples dominated by uncharacterized bacteria. These MAGs add to our understanding of gut microbial diversity in this critical model organism.

Oxygenic photosynthesis supplies organic carbon to the modern biosphere, but it is uncertain when this metabolism originated. It has previously been proposed^1,2 that photosynthetic reaction centres capable of splitting water arose by about 3 billion years ago on the basis of the inferred presence of manganese oxides in Archaean sedimentary rocks. However, this assumes that manganese oxides can be produced only in the presence of molecular oxygen³, reactive oxygen species^4,5 or by high-potential photosynthetic reaction centres^6,7. Here we show that communities of anoxygenic photosynthetic microorganisms biomineralize manganese oxides in the absence of molecular oxygen and high-potential photosynthetic reaction centres. Microbial oxidation of Mn(II) under strictly anaerobic conditions during the Archaean eon would have produced geochemical signals identical to those used to date the evolution of oxygenic photosynthesis before the Great Oxidation Event^1,2. This light-dependent process may also produce manganese oxides in the photic zones of modern anoxic water bodies and sediments.