Newfound groups of bacteria are mixing up the tree of life

June 17, 2015

By Robert Sanders, UC Berkeley Media Relations

BERKELEY — University of California, Berkeley, scientists have identified more than 35 new groups of bacteria, clarifying a mysterious branch of the tree of life that has been hazy because these microbes can’t be reared and studied in the lab.

Diagram of the tree of life with life evolving from Archaea

The new groups make up more than 15 percent of all known groups or phyla of bacteria, the scientists say, and include the smallest life forms on Earth, microbes a mere 400 nanometers across. The number of new bacterial phyla is equal to all the known animal phyla on Earth. The scientists, who recently also identified nine new groups of microbes known as Archaea, see these new additions to life on Earth as a sign that the accepted tree of life – a division into the three domains of eukaryotes, which includes animals and plants, bacteria and Archaea – needs to be revised. “This is a new view of the tree of life,” said lead author Jill Banfield, a professor of earth and planetary science and of environmental science, policy and management. “These new groups of bacteria and Archaea are changing our understanding of the number and arrangement of branches on the tree of life.” Graduate student Christopher Brown, Banfield and their colleagues reported the discovery online (Monday, June 15) in the journal Nature. Banfield is also a researcher in the Earth Sciences Division at Lawrence Berkeley National Laboratory.