Skip to main page content
Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
, 523 (7559), 208-11

Unusual Biology Across a Group Comprising More Than 15% of Domain Bacteria


Unusual Biology Across a Group Comprising More Than 15% of Domain Bacteria

Christopher T Brown et al. Nature.


A prominent feature of the bacterial domain is a radiation of major lineages that are defined as candidate phyla because they lack isolated representatives. Bacteria from these phyla occur in diverse environments and are thought to mediate carbon and hydrogen cycles. Genomic analyses of a few representatives suggested that metabolic limitations have prevented their cultivation. Here we reconstructed 8 complete and 789 draft genomes from bacteria representing >35 phyla and documented features that consistently distinguish these organisms from other bacteria. We infer that this group, which may comprise >15% of the bacterial domain, has shared evolutionary history, and describe it as the candidate phyla radiation (CPR). All CPR genomes are small and most lack numerous biosynthetic pathways. Owing to divergent 16S ribosomal RNA (rRNA) gene sequences, 50-100% of organisms sampled from specific phyla would evade detection in typical cultivation-independent surveys. CPR organisms often have self-splicing introns and proteins encoded within their rRNA genes, a feature rarely reported in bacteria. Furthermore, they have unusual ribosome compositions. All are missing a ribosomal protein often absent in symbionts, and specific lineages are missing ribosomal proteins and biogenesis factors considered universal in bacteria. This implies different ribosome structures and biogenesis mechanisms, and underlines unusual biology across a large part of the bacterial domain.

Similar articles

See all similar articles

Cited by 243 articles

See all "Cited by" articles


    1. Proc Natl Acad Sci U S A. 2013 Jun 25;110(26):E2390-9 - PubMed
    1. Annu Rev Biochem. 2011;80:501-26 - PubMed
    1. Nucleic Acids Res. 2005 Jan 19;33(2):478-85 - PubMed
    1. Syst Appl Microbiol. 2014 Feb;37(1):35-41 - PubMed
    1. Nat Protoc. 2009;4(3):363-71 - PubMed

Publication types