Origins of Life

4. Origins of Life

Since 1996 our lab has been engaged in a variety of chemical studies related to the origin of life. Our guiding principal is that the origin of life was a geochemical processes that resulted from interactions of oceans, atmosphere, and rocks and minerals. Any plausible origins scenario must be consistent with geochemical constraints. Much of our work has focused on environments at moderately high temperatures (<300ºC) and pressures (to 5,000 atmospheres).

Brandes, J.A., N.Z.Boctor, G.D.Cody, B.A.Cooper, R.M.Hazen, and H.S.Yoder, Jr. (1998) Abiotic nitrogen reduction in the early earth. Nature 395, 365-367.

Cody, G.D., N.Z.Boctor, T.R.Filley, R.M.Hazen, J.H.Scott, H.S.Yoder, Jr. (2000) Primordial carbonylated iron-sulfur compounds and the synthesis of pyruvate. Science 289, 1337-1340.

Brandes, J.A., R.M.Hazen, H.S.Yoder, Jr., and G.D.Cody (2000) Early pre- and post-biotic synthesis of alanine: an alternative to the Strecker synthesis. In: Perspectives in Amino Acid and Protein Geochemistry. (G. A. Goodfriend, M. J. Collins, M. L. Fogel, S. A. Macko, and J. F. Wehmiller, eds.). Oxford University Press, NY. pp. 41-59.

Hazen, R.M. (2001) Hazen, R.M. (2001) Emergence and the origin of life. In: G.Pályi (Editor) Fundamentals of Life. New York: Elsevier, pp.41-50.

Cody, G.D., R.M.Hazen, J.A.Brandes, H.J.Morowitz, H.S.Yoder, Jr. (2001) Geochemical roots of autotrophic carbon fixation: Hydrothermal experiments in the system citric acid, H2O-(±FeS)-(±NiS). Geochim. Cosmochim. Acta, 65, 3557-3576.

Cody, G.D., N.Z.Boctor, J.A.Brandes, T.R.Filley, R.M.Hazen and H.S.Yoder, Jr. (2004) Assaying the catalytic potential of transition metal sulfides for prebiotic carbon fixation. Geochimica et Cosmochimica Acta 68, 2185-2196.

Hazen, R. M. (2005) Genesis: The Scientific Quest for Life’s Origin. Washington, DC: Joseph Henry Press, 339 p. (Softcover edition, 2007)

Hazen, R. M. (2005) Genesis: Rocks, minerals and the geochemical origin of life. Elements 1, #3 (June, 2005), 135-137.

Hazen, R. M. and D. Deamer (2007) Hydrothermal reactions of pyruvic acid: synthesis, selection, and self-assembly of amphiphilic molecules, Origins of Life and Evolution of the Biosphere 37, 143-152.

Ertem, G, R. M. Hazen and J. P. Dworkin (2007) Sequence analysis of trimer isomers formed by montmorillonite catalysis in the reaction of binary monomer mixtures. Astrobiology 7, 715-724.

Bada, J., B. Fegley Jr., S. L. Miller, A. Lazcano, H. J. Cleaves, R. M. Hazen and J. Chalmers (2007) Debating evidence for the origin of life on Earth. Science 315, 937-938.

Ertem, G., R. M. Hazen, A. M. Snellinger, J. P. Dworkin and M. V. Johnston (2008) Sequence- and region-selective formation of RNA-like oligomers by montmorillonite catalysis. International Journal of Astrobiology, in press.

Hazen, R. M. (2008) The chemical evolution of life: An Introduction. In L. Zaikowski and J. M. Friedrich [editors], Chemical Evolution II: From Origins of Life to Modern Society. American Chemical Society Symposium, in preparation.

Hazen, R.M. (2008) The geochemical origin of life. Invited chapter in A. H. Knoll, D. E. Canfield and K. O. Konhauser (Editors), A Geobiology Reader, in preparation.

 

Many of our experiments employ gold tube reactors, which are placed in cold-seal pressure vessels with internal or external heating.

In our first set of experiments in 1996 we found that CO2 + H2O + Fe metal resulted in rapid production of a suite of alkanes and other hydrocarbons. This process appears to occur in many high P and T geochemical environments when a reduced transition metal is present.

 

In subsequent experiments we found that Ni and Co minerals also promote hydroformylation (the insertion of CO groups).

 

In work led by George Cody, we documented the possible roles of a variety of transition metal sulfides in promoting reactions that increase the carbon number of small organic molecules, both by Fischer-Tropsch-type reactions and by hydroformylation.

 

An important finding of this work is that minerals can play roles as reactants, as well as catalysts. We observe the formation of organic sulfides, iron pentacarbonyl, and as yet unidentified aqueous complexes of iron and organic ligands.

Some of our early experiments were on pyruvic acid, which rapidly reacts at modest temperature (to 350ºC) and pressure (to 4,000 atmospheres) to form a yellow-brown oily substance.

In GCMS this material displays a complex “humpane” spectrum.


Hazen and Deamer (2007) showed that hydrothermal reaction of pyruvate produce suites of molecules that self-organize in water to form these beautiful fluorescent vesicles.


Thin-layer chromatography plates of the chloroform-soluble pyruvate products (A) and Murchison meteorite extracts (B) show strikingly similar patterns.


Bumpass Hell, Mt. Lassen, California. In studies with Dave Deamer, we examined the interaction of clay minerals with small organic molecules poured into boiling ponds. We found (not surprisingly) that clay minerals quickly adsorb many different kinds of organic molecules in these environments.