Fig. 2

Several cases showing the dynamics of the model system when the Nrr’s effect is not “applied on a global scale”. Based on the case shown in Fig. 1a, at step 1.4 × 10⁶, P _NRR is changed from 0 to (a) 0.5; (b) 0.02. Based on the case shown in B, (c) at step 1.5 × 10⁶, F _SFR is changed from 2 to 10; (d) at step 1.8 × 10⁶, P _BBR is changed from 2 × 10⁻⁶ to 2 × 10⁻⁵. Note that at step 1.4 × 10⁶, due to random mutation, apparently only a portion of the RNA chromosome molecules maintains the “non-functional” Nrr gene (see the descending of black stars, which denote the five-gene chromosome, and the rising of black x-shapes, which denote the four-gene chromosome). So when the activity of the Nrr is turned on at this moment, the Nrr’s effect is only “applied on a limited scale”. The thorough genetic takeover shown in D is in fact originated from a single individual, because at step 1.8 × 10⁶ in this case there are actually only one protocell containing the five-gene chromosome, which bears the moderate Nrr gene