Evolution of resistance to pain-inducing neurotoxins: the bark scorpion-grasshopper mouse system.

了解生物体适应环境的分子变化是进化生物学的一个中心主题。随着世界范围内栖息地的丧失和全球气候变化的加速，以及人类接触到以前从未遇到过的病原体（如艾滋病毒），环境变化的步伐加快，分子进化过程对我们的生存和这个星球上许多生物的生存至关重要。本项目将研究居住在沙漠中的蚱蜢对蝎子毒液离子通道的抗性进化。蚱蜢以蝎子为食，当被蜇时，它们对蝎子的毒液没有不良反应，而蝎子的毒液会引起剧烈的疼痛和/或杀死其他和它们一样大的哺乳动物。这一提议将集中于在痛觉神经元中表达的钠离子通道基因的分子进化。本文将从遗传、生理和分子水平上研究蝗虫小鼠对蝎子毒液的疼痛敏感性的物种和个体差异，并确定这些差异对这些独特小鼠的行为和生态的影响。该项目还将进一步了解神经系统如何处理疼痛刺激。该项目代表了德克萨斯大学（一所主要的研究型大学）和萨姆休斯顿州立大学（一所非博士学位授予机构，其中许多学生来自代表性不足的群体）之间的合作关系。我们将从这两所大学招收本科生，重点招收代表性不足的少数族裔。此外，该项目将制作一盘关于树皮蝎-蚱蜢-老鼠系统共同进化的录像带，作为动物如何在恶劣的沙漠环境中生存的例子。这盘录像带将在德克萨斯纪念博物馆展出。最后，我们之前在这个系统上的工作已经引起了媒体的兴趣，并计划在国家地理电视特别节目中突出它。

Understanding the molecular changes by which organisms adapt to their environments is a central theme of evolutionary biology. With the pace of environmental change quickening due to loss of habitat worldwide and accelerated global climate change, and the exposure of humans to previously unencountered pathogens (such as HIV), the processes of molecular evolution are key to our survival and the survival of many organisms on this planet.This project will study the evolution of resistance to scorpion venom, in ion channels, of desert-dwelling grasshopper mice. Grasshopper mice prey on scorpions and, when stung, show no adverse effects to scorpion venoms that cause intense pain and/or kill other mammals their size. This proposal will focus on the molecular evolution of a sodium ion-channel gene that is expressed in pain-sensing neurons. Species and individual differences in pain sensitivity of grasshopper mice to scorpion venom will be studied on the genetic, physiological and molecular levels, and the consequences of these differences for the behavior and ecology of these unique mice will be determined. This project will also gain further understanding of how the nervous system processes painful stimuli. This project represents a partnership between the University of Texas, a major research university, and Sam Houston State University, a non-PhD granting institution with many students from underrepresented groups. We will recruit undergraduates from both institutions, focusing on underrepresented minorities. Additionally, this project will produce a videotape on co-evolution with the bark scorpion-grasshopper mouse system as an example of how animals make a living in the harsh desert environment. The videotape will be featured in an exhibit at the Texas Memorial Museum. Finally, our previous work on this system has already attracted interest from the media and there are plans for it to be highlighted in a National Geographic television special.