QCB Seminar featuring David Deamer

Join us for our QCB Seminar featuring David Deamer, UC Santa Cruz. Presentation begins at 2pm in Beckman 3269 and on Zoom, coffee and snacks served in the 3rd Floor TCBG Courtyard (outside room 3151) beginning at 1:30pm. 

Title: Nucleic acids were likely to be present on the early Earth before life began

Abstract: Were nucleic acids like DNA invented by the first forms of life four billion years ago? Or were nucleic acids synthesized by natural processes before life began? I will describe how we are using nanopore sequencing to explore processes by which nucleic acids could have emerged on the early Earth four billion years ago. Our approach to the question of life’s origin is unique. Instead of focusing solely on laboratory experiments and then assuming that the results are somehow related to conditions four billion years ago, we visit volcanic sites referred to as prebiotic analogues. The idea is to understand what the early Earth was really like, then to use that to guide what we do in the laboratory. An ubiquitous feature of analogue sites like Yellowstone, Bumpass Hell in northern California and volcanic areas of New Zealand and Kamchatka is freshwater hot springs that undergo cycles of wetting and drying. In 2008 (1) we reproduced those cycles in the laboratory and made a surprising discovery: wet-dry cycles provide a source of energy that causes mononucleotides to polymerize into nucleic acids. We have recently used nanopore sequencing and mass spectrometry to confirm the reaction (2). Two conclusions follow from these results: 1. Freshwater hot springs are more plausible than salty seawater as a site conducive for the origin of life. 2. Nucleic acids were not invented by primitive forms of life. Instead, polymers resembling nucleic acids would have been generated by wet-dry cycles and then accumulated in volcanic hot springs on the early Earth. Life began when some of the nucleic acids evolved the ability to reproduce and were then encapsulated in microscopic membranous compartments.

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