Myth and fact in the origins of cellular life on Earth

Abstract

[eng] Research into the origins of the first protocell is of a multidisciplinary nature. It draws evidence from what we know about the Earth's early atmosphere and environment, and about the most ancient features of the cell's structure and composition. Such data provides the input for the hypothesis generation and experimental reconstruction necessary to mimic steps in the formation of the first protocell. While research into the origins of the first protocell is condemned to focus upon laboratory experiments, it should be guided by a detailed study of real evidence pertaining to the environment on Earth 4 billion years ago. In this review, we take stock of the research that has been performed to date across the main disciplines of earth sciences, biochemistry, and molecular biology. We seek to identify the progress made in laying down a sequence for the events that led up to the first protocell. We also assess the strengths and weaknesses of the experimental designs and suggest some future approaches. While the field has made many important advances, from the original Stanley Miller experiment establishing 'life from chemistry' products such as amino acids, through to Deamer's findings on fatty acid membranes and Szostack's work on lipids, there is still a long and challenging journey ahead to understand how cellular life began. The experiments required to make more rapid progress in the field will likely be more elaborate, costly, and time consuming.