Christopher Lepper

Doctor of Philosophy, (Bio Physics)
Study Completed: 2015
College of Sciences


Thesis Title
Effects of High Pressure on DNA and its Components

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The exact nature of the first forms of life remains unknown along with the conditions under which they originated. Mr Lepper''sresearch used nuclear magnetic resonance (NMR) spectroscopy, with a specially designed cell and handling apparatus, to study the effects of high-pressure conditions on the thermostability of DNA and its components. He observed that the chemical stability of the nucleobase cytosine at 100 degrees Celsius was significantly decreased under high pressure conditions (up to 2500 atmospheres). The physical stability of short DNA oligonucleotides under high pressure conditions depended upon the nature of the sequence, while the effects of pressure on the physical stability of an i-motif structure was observed to be dependent on the pressure-induced changes in the pKa of cytosine. These studies have shown that a high-pressure origin of life involving cytosine is strongly disfavoured.

Professor Geoff Jameson
Dr Patrick Edwards
Professor Bill Williams