SGER: Spontaneous Mutation in the Moth, Heliothis virescens

基因突变可以由外部诱变剂如化学诱变剂或辐射引起，也可以在没有外部诱变剂影响的情况下发生。转座因子引起的自然诱变主要是从果蝇的研究中了解的；当一个基因受到另一个基因运动的影响而导致表型变化时，就会发生突变。在毛里求斯果蝇中，可以观察到一种水手元件的活性，即由Mos1基因控制的眼睛中出现高频率的镶嵌或斑点（Hartl, 2001）。虽然许多转座因子似乎已经沉默，在宿主基因组中留下一个非活性序列，但其调控机制尚不清楚。除了果蝇之外，很少有自然诱变的模型。本项目的目的是建立一种新的自然诱变遗传模型，重点了解一种名为Heliothis virescens（鳞翅目：夜蛾科）的飞蛾系中色素沉着（黑眼、金眼等）和图案（条纹眼）的多重自发突变产生的机制。虽然这种现象有许多可能的机制，但本项目将集中在一个有效的假设上，即每种不同的表型都是由相应基因的突变控制的。每个假定的基因将被纯化，同时收集有关改变色素沉着机制的生理数据，以便随后确定突变和任何新的遗传机制。这个项目有可能推翻上述假设；然而，在这种情况下，这种方法将提供适用于另一种假设的信息。发现一种新型的自然诱变的意义，如果存在，将在推进真核生物遗传学的基础科学，导致科学应用，造福社会。了解突变的目前和预期应用的例子包括防御遗传武器和对蚊子和其他害虫的遗传控制。

Genetic mutation can be caused by external mutagenic agents such as chemical mutagens or radiation, or it can occur without the impact of external agents. Natural mutagenesis due to transposable elements is understood primarily from research in fruit flies; it results when a gene is affected by the movement of another gene causing a change in phenotype. Activity of a Mariner element was observable in Drosophila mauritiana as a high frequency of mosaicism or speckling in the eye controlled by the Mos1 gene (Hartl, 2001). Although it appears that many transposable elements have become silenced leaving an inactive sequence in the host genome, the mechanism of regulation is not understood. There are few models of natural mutagenesis apart from those in fruit flies. The objective of this project is to develop a new genetic model for natural mutagenesis, focusing on understanding the mechanism by which multiple spontaneous mutations of pigmentation (black eye, golden eye, et al.) and patterning (striped eye) arose in a lineage of a moth, Heliothis virescens (Lepidoptera: Noctuidae). While there are many possible mechanisms for this phenomenon, this project will focus on one working hypothesis that each of the various phenotypes is controlled by mutation in a corresponding gene. Each putative gene will be purified while gathering physiological data on mechanisms of altered pigmentation so that the mutations and any novel genetic mechanism involved can be identified subsequently. This project bears the risks of disproving the stated hypothesis; however, in that case this approach will provide information applicable to an alternate hypothesis. The significance of discovering a new type of natural mutagenesis if present will be in advancing the basic science of eukaryotic genetics leading to scientific applications to benefit society. Examples of present and anticipated applications of understanding mutation include defense against genetic weapons and genetic control of mosquitoes and other pests.