Protocells in the Archaean Rock Record: Implications for the Origin of Life and Detection of Biosignatures

Projektbeschreibung

Protozellen in alten Gesteinen betrachten

Frühe rudimentäre Zellformen, die vor der Entwicklung komplexeren zellulären Lebens existiert haben könnten, werden als Protozellen bezeichnet. Das Team des vom Europäischen Forschungsrat finanzierten Projekts ProtoSigns erkundet die mögliche Betrachtung fossilisierter Protozellen in frühen Gesteinsformationen. Das Hauptziel besteht darin, besser zur verstehen, wie sich frühe Protozellen mit einfachen Membranen und molekularen Maschinen zu komplexeren Formen entwickelt haben. Die Forschenden werden einen neuartigen Mikrofluidikansatz zur experimentellen Erzeugung von Protozellen mit zunehmender Komplexität anwenden, wobei frühe archäische Bedingungen simuliert werden. Mit modernsten Verfahren werden die resultierenden Mikrostrukturen charakterisiert, wodurch die Erkennung von Schlüsselindikatoren in den geologischen Aufzeichnungen möglich wird, was potenziell unser Verständnis des Ursprungs und der Evolution des Lebens revolutionieren wird.

Ziel

Fossilised remains of protocells transitioning towards the first living organisms may be observable in the early rock record distorting our interpretation of biosignatures. Protocells cellular structures existing prior to the emergence of life would have comprised simple membranes and molecular machinery. The formation of complex protocells is poorly understood. The interpretation of fossilised microorganisms in the early rock record is steeped in controversy. The potential for abiotic microstructures to further complicate this interpretation has long been recognised but has not been systematically tested. Evidence suggests that prebiotic structures are very difficult to distinguish from microfossils. However, little is known about the chemical and physical characteristics of these biomorphs that may enable us to tell the difference. This project will use a novel microfluidic approach to expand the experimental scope for formation of protocells of increasing complexity. Resulting microstructures will undergo silicification and diagenesis, the principal preservation pathway for early Archean microfossils. State-of-the-art analytical techniques will be used to characterise biomorphs, providing the first rigorous investigation of the feasibility of protocell preservation and how this might express in the geological record. These data combined with a predictive model and biological controls will allow for identification of key observables that will act as biogenicity indicators. Purported microfossils will then be examined and reinterpreted using the novel biosignatures. This project has the capacity to represent a paradigm shift in our fundamental understanding of the origin and evolution of life on Earth and possibly elsewhere in the Solar System. Collectively this will represent a major advance in our understanding of the geological record, providing the first comprehensive methodology to distinguish between abiotic, prebiotic, and biological microstructures.