Journal of Molecular Evolution

, Volume 44 , Issue 6 , pp 632 –636

Relationships Between Genomic G+C Content, RNA Secondary Structures, and Optimal Growth Temperature in Prokaryotes

  • Nicolas  Galtier
  • J.R.  Lobry

DOI: 10.1007/PL00006186

Cite this article as:
Galtier, N. & Lobry, J. J Mol Evol (1997) 44: 632. doi:10.1007/PL00006186

Abstract.

G:C pairs are more stable than A:T pairs because they have an additional hydrogen bond. This has led to many studies on the correlation between the guanine+cytosine (G+C) content of nucleic acids and temperature over the last 20 years. We collected the optimal growth temperatures (Topt) and the G+C contents of genomic DNA; 23S, 16S, and 5S ribosomal RNAs; and transfer RNAs for 764 prokaryotic species. No correlation was found between genomic G+C content and Topt, but there were striking correlations between the G+C content of ribosomal and transfer RNA stems and Topt. Two explanations have been proposed—neutral evolution and selection pressure—for the approximate equalities of G and C (respectively, A and T) contents within each strand of DNA molecules. Our results do not support the notion that selection pressure induces complementary oligonucleotides in close proximity and therefore numerous secondary structures in prokaryotic DNA, as the genomic G+C content does not behave in the same way as that of folded RNA with respect to optimal growth temperature.

Key words: Prokaryotes — Optimal growth temperature — G+C content — Secondary structures — Parity rule — Directional mutation pressure

Copyright information

© Springer-Verlag New York Inc. 1997

Authors and Affiliations

  • Nicolas  Galtier
    • 1
  • J.R.  Lobry
    • 1
  1. 1.CNRS UMR 5558-Laboratoire BGBP, Université Claude Bernard, 43 Bd. du 11-NOV-1918, F-69622 Villeurbanne cedex, FranceFR