Table 3. Summary of segregation patterns at weak and strong binding conditions.

Parameters	Segregation pattern of response times in	Abundances of various types of FFLsas in Ref [10]	Source
Condition I	P-P> N-P> C1> I4> C4> I1> I3> C2> N-N >P-N > I2> C3
Condition II	{I3, C4} > {C1, I4, N-P} > {P-P, I1}, {C2> {N-N, I2} > C3}, P-N	C1> I1> C3> C2> {C4, I3, I4}	Prokaryotes
Condition III	{C4> I3} > {C1, P-P, N-P, I4} > I1, {C2> {N-N, I2} > C3}, P-N	C1> I1> C2> I2> I3	Eukaryotes (yeast)
Condition IV	{C4> I3} > {C1, P-P, N-P, I4}, {C2> {N-N, I2} > C3}, {P-N, I1}	I1 will be much lower than C1 type.	Higher eukaryotes

Note: This table summarizes the behavior of various FFLs under strong and weak binding conditions as well as fast and slow promoter-state dynamics. Under weak binding conditions ( 1) each FFL behaves differently from each other with respect to changes in . Here the settings for Condition I: weak binding and fast promoter state dynamics ( = 0.0003,  = 4,  = 1). Condition II: strong binding and fast promoter state dynamics ( = 0.0003,  = 4,  = 0.001). Condition III: strong binding and slow promoter state dynamics ( = 0.003,  = 4,  = 0.001). Condition IV: strong binding and slow promoter state dynamics ( = 0.03,  = 4,  = 0.001). Under strong binding conditions 0.001, the entire set of FFLs segregates approximately into three subgroups I, II and III. Here P-P (C1 type FFL with AND type logic on TF gene C) and I1 behaves similarly and therefore the advantages of I1 type FFL whose response time is lower than the generation time will be shared by P-P type which will be added up to the C1 type FFL with OR type gated logic to TF gene C. However this pattern seems to be weakly dependent on . When increases as in case of eukaryotic cell, then P-P behaves similar to C1 type and I1 type FFL will have the entire advantage of having lower response times than other subgroups of Group I. As a result, I1 type FFL will be more abundant in eukaryotes than prokaryotes. All these results are not dependent on changes in , increasing beyond 0.03 or decreasing below 0.0003. One should note that the physiological value of in prokaryotes will be ∼ 4. The overall response time of first subgroup (I3 and C4) of Group I is higher than the generation time of the cell. The response times of the second subgroup (C1, I4 and N-P) are closer to the generation time whereas the third subgroup possess lesser response times than the others. The response times of the FFLs in Group-I are more robust against changes in over the physiological values than Group II and III. Comparison with the relative abundances of naturally occurring FFLs, one can conclude that those FFLs are naturally selected when their response times are (a) robust against changes in and (b) closer to or lesser than the generation time.