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Titel:
Evolution in Systems of Ligation-Based Replicators
Author(s):
Bärbel M. R. Stadler,
Peter F. Stadler,
Peter R. Wills
Abstract:
The population dynamics of macromolecules that reproduce by means of
template-directed ligation of two fragments are shown to be represented by
a replicator equation with a special non-linear response function. This
result is obtained through detailed consideration of the mechanism of
ligation autocatalysis. In contrast to treatments which involve
simplification to a parabolic growth law and the expectation of global
coexistence of all species, we find that strong selection can take place in
such systems, even when there is slow uncatalysed synthesis of replicators.
Also, systems of this type are subject to invasion by new species that have
a selective advantage. An expression is derived for the survival threshold
in terms of species parameters and it is shown that this threshold depends
on the total concentration of all species in the system. For a plausible
distribution of species parameters, the number of surviving species
coexisting above the threshold increases monotonically with increasing
concentration. Illustrative numerical simulations are presented.
Keywords:
Autocatalytic Reaction Networks,
Parabolic Growth,
Extinction Threshold,
Metadynamics
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