The chemistry-biology interface and the origin of cells and viruses

10 October 2017, 1.00 PM - 10 October 2017, 2.00 PM

Eugene Koonin

Reynolds Lecture Theatre (Wills Memorial Building G25)

Sollas Lecture - The chemistry-biology interface and the origin of cells and viruses

Origin and the earliest stages in the evolution of life arguably are the hardest problems in biology. Comparative analysis of modern life forms offers little insight into primordial evolution. However, it can be complemented by the ‘chemistry conservation principle’ whereby the fundamental features of the chemical composition of cells, in particular, inorganic ion balance, have been conserved through the entire course of cellular evolution. All cells contain much more potassium, phosphate, and transition metals than modern as well as reconstructed primaeval oceans, lakes, or rivers. Given that the first cells could possess neither ion-tight membranes nor membrane pumps, the concentrations of small inorganic molecules and ions within protocells and in their environment would equilibrate. Hence, ‘chemistry conservation’: the ion composition of modern cells might reflect the inorganic ion composition of the habitats of protocells. Combining this principle with geochemical data, we come to an unexpected conclusion: the precellular stages of evolution might have transpired in shallow ponds of condensed and cooled geothermal vapor that were lined with porous silicate minerals mixed with metal sulfides and enriched in K+, Zn2+, and phosphorous compounds. In addition to the chemistry of the primordial life forms, we also attempt to reconstruct their genetic processes and genomic architecture. I will argue that molecular biology and genomics of extant viruses and other mobile genetic elements, which are associated with all cellular life forms, can inform such reconstructions. The earliest stages of evolution involved a pool of virus-like genetic elements with diverse genetic cycles.

Please note that lunch will be provided after the talk in the Earth Sciences Common Room

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