The numerical simulations show distinct kinetics in the presence of the breakage mechanism and in the absence thereof. (a) Typical kinetics observed in the numerical simulations of the growth/breakage mechanism (monomers in black, trimers in green, tetramers in red and hexamers in blue). (b) Computational determination of the order in replicator r in the case of a growth/breakage mechanism. (c) Computational determination of the replication order in the case of an elongation-only (breakage-free) mechanism. (d) Fibre length distribution as a function of time. After an initial transient regime, replication occurs at a steady-state length distribution.