The Origin of Life in the Light of Evolution

Original Abstract

The origin of life is often framed primarily as a chemical problem, yet life's defining feature is evolution. Advances in geochemistry, prebiotic chemistry, and molecular biology have produced diverse scenarios for the emergence of genomes, metabolism, and cellular compartments on the early Earth, but most of these models lack a population-genetics framework. Here, we argue that origin-of-life research must expand from asking simply how life began to exploring how it evolved from pre-biological systems. Synthesizing evidence from comparative genomics, phylogenetics, biochemistry, and geoscience, we emphasize that the last universal common ancestor (LUCA) was already a complex, ecologically adapted population far removed from the starting point of life, implying a deep pre-LUCA evolutionary history. We highlight how population genetics, ecology, and synthetic biology can constrain origin-of-life scenarios by making explicit the roles of selection, drift, mutation, horizontal gene transfer, parasites, and compartmentalization in shaping early communities. Finally, we outline an evolutionary research agenda spanning protometabolic and autocatalytic networks, protocells, the emergence of translation, and the transition to DNA genomes, in which qualitative models can now be buttressed and formalized by evolution-driven hypotheses subject to testing using theory and laboratory experiments, including those with synthetic cells.