Détection d'ADN par spectroscopie SERRS et interactions entre nucléotides et surfaces des minéraux phyllosilicatés ferromagnésiens dans le contexte de l'origine de la Vie

摘要

The first goal of this thesis was the development of a non-enzymatic DNA detection method. Current enzymatic techniques such as Polymerase Chain Reaction (PCR) often fail in analyzing ancient or processed samples. Indeed DNA undergoes numerous post-mortem degradations, among which some are known to block the bypass of DNA-polymerases. Our method combines hybridization and SERRS (Surface Enhanced Resonant Raman Scattering) spectroscopy, and allows the detection and quantification of degraded DNA sequences that are refractory to PCR analysis. This novel detection method therefore opens new perspectives, especially in paleogenetics. This thesis also aims at studying the role of mineral surfaces in the origin of nucleic acids. Mineral surfaces might have trapped and concentrated the elementary bricks of those biopolymers, thus contributing in their formation. Previous work has focused on minerals such as montmorillonite, although it might not have been abundant during the Hadean/Archean. The primitive Earth’s mineralogy would have been preferentially dominated by Fe-Mg rich phyllosilicates. We have therefore studied the adsorption of nucleotides on minerals we think are relevant to the geological context, and have varied the environmental conditions. This work allows characterizing the adsorption mechanism of nucleotides on mineral surfaces, as well as environmental conditions of the origin of genetic material.