Differences in lateral gene transfer in hypersaline versus thermal environments

Matthew E. Rhodes*, John R. Spear, Aharon Oren, Christopher H. House

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

26 Scopus citations


Background: The role of lateral gene transfer (LGT) in the evolution of microorganisms is only beginning to be understood. While most LGT events occur between closely related individuals, inter-phylum and inter-domain LGT events are not uncommon. These distant transfer events offer potentially greater fitness advantages and it is for this reason that these "long distance" LGT events may have significantly impacted the evolution of microbes. One mechanism driving distant LGT events is microbial transformation. Theoretically, transformative events can occur between any two species provided that the DNA of one enters the habitat of the other. Two categories of microorganisms that are well-known for LGT are the thermophiles and halophiles. Results: We identified potential inter-class LGT events into both a thermophilic class of Archaea (Thermoprotei) and a halophilic class of Archaea (Halobacteria). We then categorized these LGT genes as originating in thermophiles and halophiles respectively. While more than 68% of transfer events into Thermoprotei taxa originated in other thermophiles, less than 11% of transfer events into Halobacteria taxa originated in other halophiles. Conclusions: Our results suggest that there is a fundamental difference between LGT in thermophiles and halophiles. We theorize that the difference lies in the different natures of the environments. While DNA degrades rapidly in thermal environments due to temperature-driven denaturization, hypersaline environments are adept at preserving DNA. Furthermore, most hypersaline environments, as topographical minima, are natural collectors of cellular debris. Thus halophiles would in theory be exposed to a greater diversity and quantity of extracellular DNA than thermophiles.

Original languageAmerican English
Article number199
JournalBMC Evolutionary Biology
Issue number1
StatePublished - 2011

Bibliographical note

Funding Information:
We thank I. Bodaker and O. Béjà for their efforts in collecting and processing the fosmid samples, L. Tomsho for sequencing, and S. Fitz-Gibbon for bioinformatic support. This work was supported in part by the National Aeronautics and Space Administration (NASA) Astrobiology Institute (NAI) under NASA-Ames Cooperative Agreement NNA09DA76A (C.H.H.) and by the Agriculture and Food Research Initiative Competitive Grants Program Grant no. 2010-65110-20488 from the USDA National Institute of Food and Agriculture. The 454 facility at the Pennsylvania State University Center for Genome Analysis is funded, in part, by a grant from the Pennsylvania Department of Health using Tobacco Settlement Funds appropriated by the legislature.


  • Halobacteria
  • Halophile
  • Horizontal Gene Transfer
  • Thermophile
  • Thermoprotei
  • Transformation


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