Researchers have pieced together the genomes of a newly identified group of single-celled organisms, unearthing clues about their metabolism.

Archaea are different from bacteria and are generally less studied. To find new, uncultured archaea, Brett Baker at the University of Texas at Austin in Port Aransas and his colleagues extracted and analysed DNA in underwater sediment cores from estuaries in North Carolina. They reconstructed three near-complete genomes of archaea belonging to a new group that the team called Thorarchaeota. The organisms have many genes for breaking down proteins and transporting amino acids, suggesting that proteins are their main carbon source. The microbes could also be biochemically cycling sulfur in sediments.

Identification of these organisms fills in a key part of the archaeal tree of life, the authors say.

ISME J. (2016)