基因体系中若干非线性问题的理论研究-物理化学专业论文.docxVIP

涨落的存在可以使基因体系在确定性方程不发生振荡的区域发生振荡，并且可以 涨落的存在可以使基因体系在确定性方程不发生振荡的区域发生振荡，并且可以 通过内噪声随机麸抵使反应振荡达到最佳状态。同时，由于内涨藩与体系尺度密 切相关，它和体系非线性动力学机制的耦合作用，使反应具有“尺度共振”效应， 这从非线性动力学角度说明了最佳尺度的存在。此外，我们还说明了两种合成基 因网络模型，振子和双稳开关，经过耦合之后可以作为一个随机共振子来工作， 具有利用内噪声来增强基因体系性能的能力。 最后，我们还利用振荡信号研究了一种基因网络模体中的噪声特r眭。研究结 果显示，不同反馈类型的模体的噪声特性各不相同，这使得我们可以很简单的利 用基因网络单元对振荡信号的响应来获得其网络结构的一些基本性质。 Ab Ab stract The flurry of genomic research has led to detailed lists of the genes that at the heart of cellular function．These genes and their protein products form complex web of jnteractions，wherein the proteins to activate repress the transcription of the genes．The dissection and analysis ofthe complex dynamical interactions involved in gene regulation is thus natural next step in genomic research．Complex gene regulatory networks often show some nonlinear dynamical behavior．Genes may show multi—stable properties including high and low express level，leading tO the function of sensitive genetic“switch”；proteins can oscillate with time，serving for the mechanism of some important biological processes such as circadian clock．Moreover，gene expression processes mesoscopic chemical reactions that out of equilibrium state，there large internal noise involved in the processes of transcription and translation．Recently，the study of intrinsic noise in life system，specially，in gene expression processes has drawn ever—growing interests and val’iety of impoi’tant results were reported．As pointed out by McAdams et a1．，gene expression process is “noisy business”．Currently，most studies in this field focus where the noise comes fiom，how tO characterize it and what its effect is．However，some recent studies consider how the intrinsic noise systematically facilitates the system pl’operties． Therefm‘e，in this work，we interested in whether there any constructive roles of external and internal noise in mesoscopic gene expression processes． In the present work，using some nonlinear approaches，we have studied several dynamic problems in gene system．We fou