Principia Cybernetica Web


The term SYSER is an abbreviation of SYstem of SElf-Reproduction

The model of the syser was proposed independently by V.A. Ratner and V.V. Shamin, D.H. White, and R. Feistel [1-3]. .

A syser includes a polynucleotide matrix I, a replication enzyme E1, a translation enzyme E2 , and optional proteins E3 , E4, ..., En (Fig. 1).

Fig 1. The general scheme of a syser. I is the polynucleotide matrix, E1 and E2 are the replication and the translation enzymes, respectively, E3 , E4, ..., En are optional proteins.

The polynucleotide matrix I codes proteins, the replication enzyme E1 provides the matrix replication process, the translation enzyme E2 provides the protein synthesis according to an information, stored in the matrix I . We can imply that there is the translation enzyme system (consisting of several enzymes) rather than the single translation enzyme - such a substitution does not change the mathematical description of sysers. The same is valid for the replication enzyme.

Whereas hypercycles [4] can be treated as a plausible model of the origin of translation mechanisms, sysers are more similar to real biological organisms than hypercycles. Nevertheless, possible scenarios of an origin of simple sysers from small molecules were also discussed [1,2]. Contrary to the hypercycle, the syser has a universal RNA replication enzyme. The mathematical analysis of sysers [3,5,6] is similar to that of hypercycles.

Analogously to hypercycles, different sysers should be placed into different compartments for effective competition. For example, we can model the sysers' competition, using the following assumptions [7]: 1) the different sysers are placed into separate coacervates [8], 2) any coacervate volume grows proportionally to the total macromolecules synthesis rate, 3) any coacervate splits into two parts when its volume exceeds a certain critical value. During a competition, a syser, having a maximal total macromolecules synthesis rate, is selected [3,5].

The model of sysers provides the ability to analyze evolutionary stages from a mini-syser, which contains only matrix I and replication E1 and translation E2 enzymes, to protocell, having rather real biological features. Some features can be modeled by assigning certain functions to optional proteins (Fig.1). For example, "Adaptive syser" [6] includes a simple molecular control system, which "turns on" and "turns off" synthesis of some enzyme in response to the external medium change; the scheme of this molecular regulation is similar to the classical model by F. Jacob and J. Monod [9]. The mathematical models of the adaptive syser as well as that of the mini-syser are described in the child node Adaptive syser: the model of hypothetical prebiological control system .

The scheme of sysers is similar to that of the self-reproducing automata by J. von Neumann [10]. The self-reproducing automata components and their syser's counterparts can be represented as follows:

Self-reproducing automata by J. von Neumann


Linear storing chain L

Polynucleotide matrix I

Constructing automaton A for manufacturing an arbitrary automaton according to description, stored in the chain L

Translation enzyme E2

Automaton B for copying of the chain L

Replication enzyme E1

Automaton C, needed to control the whole reproduction and to separate of the produced "child" system from the "parent" one

Splitting of a coacervate during a syser growth

Conclusion. Sysers is a rather universal model of self-reproducing system. It provides the ability to analyze evolutionary stages from a very simple macromolecular systems to protocells, having real biological features.


1. V.A. Ratner and V.V. Shamin. In: Mathematical models of evolutionary genetics. Novosibirsk: ICG, 1980. P.66. V.A. Ratner and V.V. Shamin. Zhurnal Obshchei Biologii. 1983. Vol.44. N.1. PP. 51. (In Russian).

2. D.H. White. J. Mol. Evol. 1980. Vol.16. N.2. P.121.

3. R. Feistel. Studia biophysica.1983. Vol.93. N.2. P.113.

4. Eigen M. and P. Schuster. The Hypercycle: A principle of natural self-organization, Springer, Berlin, 1979

5. V.G. Red'ko. Biofizika. 1986. Vol. 31. N.4. P. 701 (In Russian).

6. V.G. Red'ko. Biofizika. 1990. Vol. 35. N.6. P. 1007 (In Russian).

7. R. Feistel, Yu. M. Romanovskii, and V.A.Vasil'ev. Biofizika. 1980. Vol. 25. N.5. P. 882. (In Russian).

8. A.I. Oparin. "The origin of life". New York, 1938. A.I.Oparin. "Genesis and evolutionary development of life". New York, 1968.

9. F. Jacob and J. Monod. J. Mol. Biol. 1961. Vol. 3. P. 318.

10. von Neumann J. Theory of Self-Reproducing Automata. (Ed. by A. W. Burks), Univ. of Illinois Press, Champaign, 1966.

Copyright© 1998 Principia Cybernetica - Referencing this page

V.G. Red'ko

Apr 27, 1998


Metasystem Transition Theory

Evolutionary Theory

Mathematical Modeling of Evolution

Models of molecular-genetic systems origin

Prev. Next

Adaptive syser


Add comment...