Encyclopedia of Astrobiology

2011 Edition
| Editors: Muriel Gargaud, Ricardo Amils, José Cernicharo Quintanilla, Henderson James (Jim) CleavesII, William M. Irvine, Daniele L. Pinti, Michel Viso


  • David MoreiraEmail author
  • Purificación López-García
Reference work entry
DOI: https://doi.org/10.1007/978-3-642-11274-4_1210



In microbiology, a phylotype is an environmental DNA sequence or group of sequences sharing more than an arbitrarily chosen level of similarity of a particular gene marker. The most widely used phylogenetic marker is the small subunit ribosomal RNA gene. Two prokaryotic sequences are generally considered as belonging to the same phylotype when they are more than 97–98% identical (for eukaryotes, the values generally used are in the 98–99% nucleotide identity range). In prokaryotic microbiology, phylotypes, often referred to as Operational Taxonomic Units (OTUs), are a proxy for  species.

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© Springer-Verlag Berlin Heidelberg 2011

Authors and Affiliations

  1. 1.Unité d'Ecologie, Systématique et Evolution - CNRS UMR8079Université Paris-Sud 11, bâtiment 360ParisFrance