Emergence of a complex unit of selection in an oligomer pool

Natural selection acts most directly on replicators, but under suitable ecological and developmental conditions its effects can filter upward, endowing collectives with heritable differences and making them effective units of selection. We present an experimentally tractable molecular case: enzyme-free RNA oligomer pools relevant to minimal laboratory life and early-life models. Short oligomers collectively encode a virtual circular genome (VCG), distributing information across many strands. Through simulations and experiments, we show that cooperation among dominant oligomers suppresses error-prone chimeras and repeat-driven instabilities, thereby preserving genomic information. This cooperation produces frequency-dependent selection, enabling the VCG to function as an evolvable individual that can emerge de novo from a random pool. Beyond origins-of-life scenarios, this system provides a minimal, controllable testbed for multilevel selection and transitions in individuality, while also addressing practical obstacles to constructing minimal life in the laboratory.