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→Coherent type 1 FFL (C1-FFL)
===Coherent type 1 FFL (C1-FFL)===
===Coherent type 1 FFL (C1-FFL)===
The C1-FFL with an AND gate was shown to have a function of a ‘sign-sensitive delay’ element and a persistence detector both theoretically <ref name="man1"/> and experimentally<ref name="man2">{{cite journal |doi=10.1016/j.jmb.2003.09.049 |vauthors=Mangan S, Zaslaver A, Alon U |title=The coherent feedforward loop serves as a sign-sensitive delay element in transcription networks |journal=J. Mol. Biol. |volume=334 |issue=2 |pages=197–204 |date=November 2003 |pmid=14607112 |citeseerx=10.1.1.110.4629 }}</ref> with the arabinose system of ''[[Escherichia coli|E. coli]]''. This means that this motif can provide pulse filtration in which short pulses of signal will not generate a response but persistent signals will generate a response after short delay. The shut off of the output when a persistent pulse is ended will be fast. The opposite behavior emerges in the case of a sum gate with fast response and delayed shut off as was demonstrated in the flagella system of ''[[Escherichia coli|E. coli]]''.<ref name="kal1">{{cite journal |vauthors=Kalir S, Mangan S, Alon U |title=A coherent feed-forward loop with a SUM input function prolongs flagella expression in ''Escherichia coli'' |journal=Mol. Syst. Biol. |volume=1 |pages=E1–E6 |year=2005 |pmid=16729041 |pmc=1681456 |doi=10.1038/msb4100010 |issue=1}}</ref> De novo evolution of C1-FFLs in [[gene regulatory network]]s has been demonstrated computationally in response to selection to filter out an idealized short signal pulse, but for non-idealized noise, a dynamics-based system of feed-forward regulation with different topology was instead favored.<ref>{{cite journal |last1=Xiong |first1=Kun |last2=Lancaster |first2=Alex K. |last3=Siegal |first3=Mark L. |last4=Masel |first4=Joanna |title=Feed-forward regulation adaptively evolves via dynamics rather than topology when there is intrinsic noise |journal=Nature Communications |date=3 June 2019 |volume=10 |issue=1 |pages=2418 |doi=10.1038/s41467-019-10388-6|pmid=31160574 |pmc=6546794 }}</ref>
The C1-FFL with an AND gate was shown to have a function of a ‘sign-sensitive delay’ element and a persistence detector both theoretically <ref name="man1"/> and experimentally<ref name="man2">{{cite journal |doi=10.1016/j.jmb.2003.09.049 |vauthors=Mangan S, Zaslaver A, Alon U |title=The coherent feedforward loop serves as a sign-sensitive delay element in transcription networks |journal=J. Mol. Biol. |volume=334 |issue=2 |pages=197–204 |date=November 2003 |pmid=14607112 |citeseerx=10.1.1.110.4629 }}</ref> with the arabinose system of ''[[Escherichia coli|E. coli]]''. This means that this motif can provide pulse filtration in which short pulses of signal will not generate a response but persistent signals will generate a response after short delay. The shut off of the output when a persistent pulse is ended will be fast. The opposite behavior emerges in the case of a sum gate with fast response and delayed shut off as was demonstrated in the flagella system of ''[[Escherichia coli|E. coli]]''.<ref name="kal1">{{cite journal |vauthors=Kalir S, Mangan S, Alon U |title=A coherent feed-forward loop with a SUM input function prolongs flagella expression in ''Escherichia coli'' |journal=Mol. Syst. Biol. |volume=1 |pages=E1–E6 |year=2005 |pmid=16729041 |pmc=1681456 |doi=10.1038/msb4100010 |issue=1}}</ref> De novo evolution of C1-FFLs in [[gene regulatory network]]s has been demonstrated computationally in response to selection to filter out an idealized short signal pulse, but for non-idealized noise, a dynamics-based system of feed-forward regulation with different topology was instead favored.<ref>{{cite journal |last1=Xiong |first1=Kun |last2=Lancaster |first2=Alex K. |last3=Siegal |first3=Mark L. |last4=Masel |first4=Joanna |title=Feed-forward regulation adaptively evolves via dynamics rather than topology when there is intrinsic noise |journal=Nature Communications |date=3 June 2019 |volume=10 |issue=1 |pages=2418 |doi=10.1038/s41467-019-10388-6|pmid=31160574 |pmc=6546794 }}</ref>
===一致前馈回路类型一(C1-FFL)===
具有与门的C1-FFL有“符号-敏感延迟”单元和持久性探测器的功能，这一点在[[大肠杆菌]]阿拉伯糖系系统的理论<ref name="man1"/>和实验上<ref name="man2">{{cite journal |doi=10.1016/j.jmb.2003.09.049 |vauthors=Mangan S, Zaslaver A, Alon U |title=The coherent feedforward loop serves as a sign-sensitive delay element in transcription networks |journal=J. Mol. Biol. |volume=334 |issue=2 |pages=197–204 |date=November 2003 |pmid=14607112 |citeseerx=10.1.1.110.4629 }}</ref> 都有发现。这意味着该模体可以提供脉冲过滤，短脉冲信号不会产生响应，而持久信号在短延迟后会产生响应。当持久脉冲结束时，输出的关闭将很快。与此相反的行为出现在具有快速响应和延迟关闭特性的加和门的情况下，这在[[大肠杆菌]]的鞭毛系统中得到了证明。<ref name="kal1">{{cite journal |vauthors=Kalir S, Mangan S, Alon U |title=A coherent feed-forward loop with a SUM input function prolongs flagella expression in ''Escherichia coli'' |journal=Mol. Syst. Biol. |volume=1 |pages=E1–E6 |year=2005 |pmid=16729041 |pmc=1681456 |doi=10.1038/msb4100010 |issue=1}}</ref>在[[基因调控网络]]的重头进化中，对于滤除理想化的短信号脉冲作为进化压，C1-FFLs已经在计算上被证明可以进化出来。但是对于非理想化的噪声，不同拓扑结构前馈调节的动态系统被优先考虑。 <ref>{{cite journal |last1=Xiong |first1=Kun |last2=Lancaster |first2=Alex K. |last3=Siegal |first3=Mark L. |last4=Masel |first4=Joanna |title=Feed-forward regulation adaptively evolves via dynamics rather than topology when there is intrinsic noise |journal=Nature Communications |date=3 June 2019 |volume=10 |issue=1 |pages=2418 |doi=10.1038/s41467-019-10388-6|pmid=31160574 |pmc=6546794 }}</ref>
===Incoherent type 1 FFL (I1-FFL)===
===Incoherent type 1 FFL (I1-FFL)===