Metagenome of marine sediment near Loki's castle

This study aims at examining the particular environment of Loki's castle, to unveil novel archaeal lineages. In particular, members of the Deep Sea Archaeal Group were carefully examined, and a composite genome, extracted from metagenomes, was assembled and analyzed. Two metagenomes were created from the same marine sediment sample. In the LokiAmp metagenome (SAMN03002195), DNA was amplified by MDA while in the Loki metagenome (SAMN03002196) it was not. Reads were corrected and assembled with SPAdes and then binned. One bin was selected for further analysis, since it was determined that contigs in that bin belonged to several, very similar (strain or species level) organisms. Contigs in this bin were filtered by coverage, to try to get as close to a single organism. Reads from Loki, corrected by SPAdes, were mapped to the whole Loki metagenome and reads mapping the selected contigs were extracted and reassembled. Contigs were then filtered again to form a composite genome (Lokiarchaeum), which is as close as possible to a single genome but is estimated to contain ~1.4 genomes. This composite genome (SAMN03002197) is a novel genus, and will probably be classified in a new phylum.