A hypothetic scheme for evolution of probionts

The origin of life cannot be assumed as a single, indissoluble chain of events. The objects we observe on this developmental pathway appeared many times in different biogenetic provinces of the Earth's surface. However, these systems might undergo decomposition and later appeared again. Such process especially might occur with the multimolecular, phase separated systems (probionts), interacting with the surrounding solution in the manner of the open systems. The modelling experiments demonstrate, that basing upon such interaction the systems could well maintain growth and passed through natural selection in the original Darwinian interpretation of this term, i.e. survival of the forms better adapted to the exterior environment. On this basis there proceeded the development of probionts organization, in particular, there arose the ‘fitness’ of molecular structure of proteins and other polymers. However, the maintenance of steady organization and selfreproduction of probionts were still far from perfection. Their evolution was still connected with the regular and strong decomposition processes. The decomposition products, which had already acquired somewhat better fittness than the original polymers, might either be assimilated by more developed probionts or enter a selfassembly process to form the new systems, like that had occured at the early stage of the development. The appearance of nucleic acids and their coding relations with proteins have provided significantly more high stability of developing probionts and primitive organisms. But on this stage, too, the decomposition andde novo formation of the developing systems had to occur. This fact makes us to approach in a new angle the problems of the origin of viruses, symbiosys and parasitism.