A large fraction of diversity of the Archaea is still poorly explored. We are targeting environmental samples to extract genomic data of archaeal lineages of specific interest from an evolutionary point of view. We will probe available sequence data from public environmental metagenomics databases to identify specific lineages. In parallel, we will produce our own data from selected environmental samples containing these lineages. These data will allow filling up poorly explored branches of the tree of Archaea and bring important information on the metabolic diversity and adaptation to various environmental conditions, including the human microbiome.