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Did nature also choose arsenic?

Felisa Wolfe-Simon¹, Paul C. W. Davies², & Ariel Anbar³

Correspondence: (Login to view email address)

1. Department of Earth and Planetary Sciences, Harvard University
2. BEYOND: Center for Fundamental Concepts in Science, Arizona State University
3. School of Earth and Space Exploration and Dept. of Chemistry and Biochemistry, Arizona State University

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Document Type:

Manuscript

Date:

Received 02 January 2008 00:46 UTC; Posted 02 January 2008

Subjects:

Chemistry, Evolutionary Biology

Tags:

• phosphorus
• arsenic
• chemistry
• Evolution

Abstract:

All known life requires phosphorus (P) in the form of inorganic phosphate (PO4- or Pi) and phosphate-containing organic molecules. Pi serves as the backbone of the nucleic acids that constitute genetic material and as the major repository of chemical energy for metabolism in polyphosphate bonds. Arsenic (As) lies directly below P on the periodic table and so the two elements share many chemical properties, although their chemistries are sufficiently dissimilar that As cannot directly replace P in modern biochemistry. Arsenic is toxic precisely because As and P are similar enough that organisms attempt this substitution. We hypothesize that ancient biochemical systems, analogous to but distinct from those known today, could have utilized arsenate in the equivalent biological role of phosphate. Organisms utilizing such “weird life” biochemical pathways may have supported a “shadow biosphere” at the time of the origin and early evolution of life on Earth or on other planets. Such organisms may even persist on Earth today, undetected, in unusual niches.

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This document is licensed to the public under the Creative Commons Attribution 3.0 License

How to cite this document:

Wolfe-Simon, Felisa, Davies, Paul, and Anbar, Ariel. Did nature also choose arsenic?. Available from Nature Precedings <http://hdl.handle.net/10101/npre.2008.1482.1> (2008)

Version info:

Published version:

10.1017/S1473550408004394 (Peer Reviewed) This is the final peer-reviewed published manuscript at the International Journal of Astrobiology. Please use this citation for this work: Felisa Wolfe-Simon, Paul C.W. Davies and Ariel D. Anbar Did nature also choose arsenic?. International Journal of Astrobiology, Published online by Cambridge University Press 30 Jan 2009 doi:10.1017/S1473550408004394

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