Frontier Leaders: Hydrothermal vents and the origin of life

Frontier Leaders of Today for the Scientists of Tomorrow

ITQB PhD Program Seminar Series

Title: Hydrothermal vents and the origin of life

Speaker: William Martin

Affiliation: Dusselforf University, DE

More Information: Poster

Abstract

The chemistry of life is the chemistry of reduced organic compounds, therefore all theories for the origin of life have to offer testable hypotheses to account for the source of these compounds. The most well-known theories for the origin of organic compounds are based on the notion of an “organic soup” that was generated either by lightning-driven reactions in the Earth’s early atmosphere or by delivery of organic compounds to the Earth from space. When submarine hydrothermal vents were discovered 30 years ago, hypotheses on the source of life’s reduced carbon started to change. Submarine hydrothermal vents are geochemically reactive habitats that harbour rich microbial communities. The chemistry of the H₂-CO₂ redox couple that is present in hydrothermal systems has striking parallels with the core energy metabolic reactions of some modern prokaryotic autotrophs (methanogens and acetogens), whose biochemistry might, in turn, harbour clues about the kinds of reactions that initiated the chemistry of life. Hydrothermal vents thus unite microbiology and geology to breathe new life into research into one of biology’s most significant questions — the origin of life.

Despite thermodynamic, bioenergetic and phylogenetic failings, the 80-year-old concept of primordial soup remains central to mainstream thinking on the origin of life. But soup is homogeneous in pH and redox potential, and so has no capacity for energy coupling by chemiosmosis. Thermodynamic constraints make chemiosmosis strictly necessary for carbon and energy metabolism in all free-living chemotrophs, and presumably the first free-living cells too. Proton gradients form naturally at alkaline hydrothermal vents and are viewed as central to the origin of life. Let us consider how the earliest cells might have harnessed a geochemically created proton-motive force and then learned to make their own, a transition that was necessary for their escape from the vents. Synthesis of ATP by chemiosmosis today involves generation of an ion gradient by means of vectorial electron transfer from a donor to an acceptor. The first electron donor was probably H₂ and the first acceptor CO₂.

Literature:
Martin W, Russell MJ: On the origins of cells: An hypothesis for the evolutionary transitions from abiotic geochemistry to chemoautotrophic prokaryotes, and from prokaryotes to nucleated cells. Phil. Trans Roy. Soc. Lond. B 358:59–85 (2003)
Russell MJ, Martin W: The rocky roots of the acetyl-CoA pathway. Trends Biochem. Sci. 29:358–363 (2004).
Martin W, Russell MJ: On the origin of biochemistry at an alkaline hydrothermal vent. Phil. Trans Roy. Soc. Lond. B 367:1887–1925 (2007).
Martin W, Baross J, Kelley D, Russell MJ: Hydrothermal vents and the origin of life. Nature Rev. Microbiol. 6:805–814 (2008).
Lane N, Allen JF, Martin W: How did LUCA make a living? Chemiosmosis in the origin of life. BioEssays, in press. 

William Martin

Main scientific interests: Evolution; Endosymbiosis, Organelles, Early evolution, Biochemical evolution

Short Biography:

1985  Degree in Biology, University of Hannover
1988   PhD in Genetics, Max Planck Institute for Breeding Research in Cologne
1989-1999 Postdoctoral Research, University of Braunschweig
1999 –  Professor of Botany at the University of Düsseldorf

Editorships

Editor-in-Chief : Genome Biology and Evolution
Editorial Board Member (past and present): Gene, Molecular Biology and Evolution, Marine Genomics, BioEssays, Environmental Microbiology, Plant Biology, European Journal of Phycology

Awards 
1989:  Max-Planck postdoctoral stipend
1990:  Heinz-Maier-Leibnitz Prize of the Deutsche Forschungsgemeinschaft
1997: Technology Transfer Prize, Industrie und Handelskammer Braunschweig
1998:  Miescher-Ishida Prize of the International Society of Endocytobiology
2008:  European Research Council Advanced Grant (€2M)

Honours
2000-2007 Foreign Associate, CIAR Programme in Evolutionary Biology
2001- Faculty 1000 Member for Plant Genomes and Evolution
2006 Elected Fellow of the American Academy for Microbiology
2006-2009 Julius von Haast Fellow of the New Zealand Ministry for Research,
 Science and Technology
2007- Selection Committee for the Heinz-Maier-Leibnitz Prize of the DFG 
2008 Elected Member of the Nordrhein-Westfälische Akademie der Wissenschaften  
2009 Elected Member of the European Research Council Review Board

Publications
Author of over 190 papers (many in Nature and PNAS), with close to 7,000 citations and h-index of 43