RESUMEN
The emergence of informational replicators was fundamental to the origin of life and self-ordering proto-replicators provide an abstract, simulation based mechanism for a possible intermediary step in their development. Single systems enabled the dynamic self-ordering of generalised subunits into coherent and mobile structures, without the pre-existence of templates, replicators or functional catalysts. Paired systems linked via probabilistic, inter-system structural movement exhibited passive competition for subunits (which produced a new level of self-ordering dependent upon the systems' relative self-ordering capabilities) and the existence of primitive membranes increased this effect. This discussion naturally extends this approach to a simultaneous linking of multiple systems. Initially for various fixed numbers of subunits, 12 simultaneously linked self-ordering proto-replicators were studied (with and without primitive membranes). Then for the same underlying systems and three rates of increase, subunits were randomly added to give subunit ranges equivalent to the fixed cases. The results show an interacting network of inter-system passive competition, which created clear orderings of environmental dominance, the range of which was increased by primitive membranes. The simulations with increasing numbers of subunits provided approximations to those with fixed numbers and potentially give access to multiple sample points for future simulations with significantly greater numbers of subunits.
Asunto(s)
Ambiente , Evolución Química , Membranas/metabolismo , Modelos Biológicos , Origen de la Vida , Simulación por ComputadorRESUMEN
Self-ordering proto-replicators provide an abstract, simulation based investigation of a possible intermediary step in the development of informational replicators. They involve the dynamic self-ordering of generalised subunits of at least two types into coherent and mobile structures, and do not require the preexistence of templates, replicators or functional catalysts. The following discussion naturally extends this approach to include pairs of such systems linked via a probabilistic, inter-system movement of structures. Initially for two specific forms of self-ordering proto-replicator, various types of probabilistic movement were studied, both with and without a simple model of a primitive membrane. Then for a specific probabilistic movement, which was again considered with and without membranes, different pairings of twelve forms of self-ordering proto-replicators were studied. The results show that the systems exhibited a form of passive competition for subunits and that this produced a new level of multi-system self-ordering that depended upon the relative self-ordering capabilities of the individual systems. This effect was also found to be significantly more pronounced for those systems that included the primitive membranes. The implications for the origins of life were then considered.
Asunto(s)
Biopolímeros/química , Membrana Dobles de Lípidos/química , Membranas Artificiales , Modelos Biológicos , Modelos Químicos , Origen de la Vida , Origen de Réplica , Simulación por ComputadorRESUMEN
Standard theories suggest that the first informational replicator involved RNA molecules (or a more primitive analogue) and that a preliminary step for the development of such replicating systems may have been the emergence of subunits capable of forming chains and interchain pairings. Following these hypotheses, this discussion describes various abstract simulations designed to investigate the structures resulting from such interactions for generalised subunits. Three classes of pairing strategy were considered for a range of subunit concentrations. The resulting dynamic self-organization of the systems produced high levels of structural complexity (some at low subunit concentrations and in the presence of disruptive subunits) and a significantly increased percentage of complementary base pairing (particularly in the more substantial structures). These properties of the systems, which did not require pre-existing replicators, templates or functional catalysts, were shown to be sensitive to the form of pairing strategy, subunit concentrations and various conditions that could theoretically be altered by products of the systems. Though no systems behaved as a replicator, some possessed collections of properties from which a replicating system might theoretically be constructed without requiring the introduction of additional classes of properties. The implications of such systems were considered with respect to the origin of life.