用于合成生物学的新颖基因控制系统的设计受数字逻辑支配。这必然是一种复杂的安排。现在Timothy Lu及其同事利用在自然细胞中所发现的模拟构造单元来在对数范畴内执行算术运算。这样的模拟回路（它们可以与数字回路集成）应能使采用更少的要素来进行在生物感应中要求宽的动态范围的复杂计算成为可能。（生物谷Bioon.com）
生物谷推荐英文摘要：
Nature doi:10.1038/nature12148
Synthetic analog computation in living cells
Ramiz Daniel, Jacob R. Rubens, Rahul Sarpeshkar & Timothy K. Lu
A central goal of synthetic biology is to achieve multi-signal integration and processing in living cells for diagnostic, therapeutic and biotechnology applications. Digital logic has been used to build small-scale circuits, but other frameworks may be needed for efficient computation in the resource-limited environments of cells. Here we demonstrate that synthetic analog gene circuits can be engineered to execute sophisticated computational functions in living cells using just three transcription factors. Such synthetic analog gene circuits exploit feedback to implement logarithmically linear sensing, addition, ratiometric and power-law computations. The circuits exhibit Weber’s law behaviour as in natural biological systems, operate over a wide dynamic range of up to four orders of magnitude and can be designed to have tunable transfer functions. Our circuits can be composed to implement higher-order functions that are well described by both intricate biochemical models and simple mathematical functions. By exploiting analog building-block functions that are already naturally present in cells, this approach efficiently implements arithmetic operations and complex functions in the logarithmic domain. Such circuits may lead to new applications for synthetic biology and biotechnology that require complex computations with limited parts, need wide-dynamic-range biosensing or would benefit from the fine control of gene expression.
