Armed with gene sequences, researchers led by the University of California, Berkeley's Jillian Banfield have drawn an expanded tree of life, marked by an abundance of bacteria.
"It is a momentous discovery — an entire continent of life-forms," Eugene Koonin from the National Center for Biotechnology Information, who was not involved in the study, tells the New York Times.
As Banfield and her colleague report in Nature Microbiology this week, they relied on new genomic data they collected from more than 1,000 uncultivated and rare species as well as some 2,000 published genomic sequences to create a tree of life based on the species' 16S rRNA genes. The resulting tree includes Archaea, Bacteria, and Eukarya, and, they note, the Bacteria domain includes more major lineages than the others — and many of these bacteria have only been identified through their genes.
"Most of life is hiding under our noses," adds the University of Nevada, Las Vegas' Brian Hedlund, who was not involved in the study.
However, the Pasteur Institute's Patrick Forterre tells the Times that identifying species solely through their DNA can be problematic. While he says bacteria do likely make up the bulk of the diversity of life, he says that genomes assembled from DNA fragments could actually be mixtures of genes from different species.