定向演化(Directed Evolution)為合成生物學中一個強而有力的工具，它可以在未知許多中間演化細節的狀態下，成功利用基因工程建構出高穩定性的系統。為了創造更多的生物變異性，並且欲量身訂做符合不同需求的單一變體(變異的範圍可以是配體、酶、工作途徑或甚至整個生物體)，此系統包含了一系列的方法及
理論。
在本研究中，我們以David Liu 在2011 年建所立的噬菌體輔助連續進化系統（PACE）為基礎進一步作修改。雖然實驗室規模的演化已經產生了許多具有特殊功能的生物小分子，但光是完成突變，基因表達，篩選或選擇一個循環，就需要數天或更長的時間，而且因著人為干擾，複雜的過程和無法精確控制的篩選。我們藉由修改M13KO7 絲狀噬菌體生命週期，以大幅度加速實驗室演化化實驗，並採用低人為干預和優化選擇，稱為噬菌體輔助自主連續定向進化-PAACDE。 藉由使用PAACDE，我們建構了識別特殊啟動子的T7RNA 聚合酶（RNAP）變體，用ATP 代替GTP 啟動轉錄本，並用CTP 啟動轉錄本。 這些過程僅僅是通過連續的細胞與細胞間溝通和進行半固態培養盤上競爭。

Directed evolution is a powerful tool in Synthetic Biology, able to bypass gaps in knowledge and capable of engineering even the most highly conserved biological processes. It encompasses a range of methodologies to create variation in a population and to select individual variants with the desired function-be it a ligand, enzyme, pathway or even whole organisms.
In this study, we based on the platform of Phage Assisted Continuous Evolution
System(PACE) created by David Liu in 2011. However, laboratory evolution has
generated many biomolecules with desired properties, but a single round of mutation,
gene expression, screening or selection, and replication typically requires days or longer with frequent human intervention, complex process, and uncontrollable selection. We build up a modified filamentous bacteriophage life cycle to dramatically accelerate laboratory evolution experiments with low human intervention and optimized selection called Phage Assisted Autonomous Continuous Directed Evolution-PAACDE. Using PAACDE, we evolved T7 RNA polymerase (RNAP) variants that recognize a distinct promoter, initiate transcripts with ATP instead of GTP, and initiate transcripts with CTP. Those process are performed just on an agar plate with continuous cell-cell communication amd racing.

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