Genomic analysis of Hyphomonas neptunium contradicts 16S rRNA gene-based phylogenetic analysis: implications for the taxonomy of the orders 'Rhodobacterales' and Caulobacterales

Int J Syst Evol Microbiol. 2005 May;55(Pt 3):1021-1026. doi: 10.1099/ijs.0.63510-0.


Hyphomonas neptunium is a marine prosthecate alpha-proteobacterium currently classified as a member of the order 'Rhodobacterales'. Although this classification is supported by 16S rRNA gene sequence phylogeny, 23S rRNA gene sequence analysis, concatenated ribosomal proteins, HSP70 and EF-Tu phylogenies all support classifying Hyphomonas neptunium as a member of the Caulobacterales instead. The possible reasons why the 16S rRNA gene sequence gives conflicting results in this case are also discussed.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Alphaproteobacteria / classification*
  • Alphaproteobacteria / genetics*
  • Bacterial Proteins / genetics
  • DNA, Bacterial / chemistry
  • DNA, Bacterial / genetics
  • DNA, Ribosomal / chemistry
  • DNA, Ribosomal / genetics
  • Genes, rRNA*
  • HSP70 Heat-Shock Proteins / genetics
  • Peptide Elongation Factor Tu / genetics
  • Phylogeny
  • RNA, Bacterial / genetics
  • RNA, Ribosomal, 16S / genetics*
  • RNA, Ribosomal, 23S / genetics
  • Sequence Analysis, DNA


  • Bacterial Proteins
  • DNA, Bacterial
  • DNA, Ribosomal
  • HSP70 Heat-Shock Proteins
  • RNA, Bacterial
  • RNA, Ribosomal, 16S
  • RNA, Ribosomal, 23S
  • Peptide Elongation Factor Tu