Sedimentary Minerals, Organic Chemical Transformations, and the Origin of Life

Our understanding of geological environments on Earth 4.35 billion years ago has advanced to the point where geology can be combined with organic chemistry that does not need careful human control to build models for how the first genetic molecules might have emerged on Earth, and possibly on other rocky planets like Mars. This "hands off" chemistry can be further simplified in the context of rocks present in those environments.

This combination now allows us to advance scientific knowledge relevant to one of the oldest questions posed by humankind: Where did we come from? Further, the simplicity of the prebiotic chemistry that this project will develop makes it accessible to students, even those in high school. In addition to advancing the science, this project will deliver kits to those students that will let them participate in the current excitement in geochemistry relevant to this "big question".

This geology-chemistry combination supports the "RNA first hypothesis" for the origin of life, which holds that Darwinian evolution emerged based on the abiological formation of ribonucleic acid that served as its first informational molecule. Here, the geological environment comprises intermittently dry, constrained aquifers that receive by rain small carbohydrates stabilized by volcanic sulfur dioxide, reduced nitrogen-containing organic molecules, and other species that were created by UV and electrical discharge in atmospheres that had been reduced by iron fragmented from the cores of impacting bodies.

The geological environment includes surrounding rocks from a redox neutral crust, including borate evaporite minerals, as well as basaltic glass generated by the impacts and volcanism on the young Earth. The basaltic glass contains dehydrated phosphates which can serve as a catalyst to assemble RNA. In this single environment, small organics can yield oligomeric RNA 100-200 nucleotides long by a process that initiates with borate-controlled maturation of stabilized carbohydrates, phosphorylation by glass-delivered polyphosphates, reaction of ribose cyclic phosphates with nucleobases to give nucleotides, with borate-moderated phosphorylation yielding nucleoside triphosphates.

This project will complete structure analysis of RNA products formed from triphosphates by impact glass, integrate carbohydrate processing with downstream nucleoside synthesis, explore the possibility of this environment producing homochiral products, and develop the sedimentary and igneous geology of relevant minerals for students to work with.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.