Altered thyroid hormone signalling in accelerated metamorphosis in desert frogs

荷尔蒙影响身体每个器官的发育，可能是生物多样性进化的基础。特别是，甲状腺激素(TH)在大脑和骨骼发育中起着关键作用，然而TH在不同脊椎动物物种的发育中所起的作用差别很大。事实上，在青蛙和火蜥蜴的生活史中发现的巨大多样性与生理上的进化变化有关。一种如此重要的荷尔蒙如何改变其在进化中的发育作用尚不清楚。为了更全面地了解TH在进化中的作用，本项目将研究TH受体(TRs)的表达变化在沙漠蛙加速变态进化中的作用。青蛙的变态依赖于TH，与非沙漠亲缘物种相比，沙漠青蛙的幼虫周期较短。根据我们的初步数据，我们推测，与非沙漠物种相比，沙漠物种对TH的反应更强烈，因为它们的幼虫周期较短。这个项目的成功完成将在功能上测试TRR表达的进化增加对变态速度的影响。这项研究的基本原理是，了解tr表达变化如何影响青蛙物种之间的变态将促进我们对这一强大的激素系统的发育和进化作用的理解。这一研究项目与教育的结合将通过让本科生和研究生不仅参与研究项目，而且通过在会议上展示成功的研究成果来实现。目前的项目通过国际合作和为本科教学提供教育材料来加强研究和教育的基础设施。拟议研究的结果将通过同行评议期刊上的出版物和专业会议上的介绍广泛传播，项目中使用的所有材料都将保存在科学界可用的研究收藏中。最后，预计这项研究将使整个社会受益，主要是通过让公众认识到进化和生物多样性的基础。

Hormones influence the development of every organ in the body and may underlie the evolution of biodiversity. In particular, thyroid hormone (TH) plays critical roles in brain and skeletal development, yet the role TH plays in development varies widely across vertebrate species. Indeed, evolutionary changes in TH physiology have been implicated in the enormous diversity found in frog and salamander life history. How such an important hormone can change its developmental role in evolution is not known. To more fully understand the role of TH in evolution, this project will examine the role of altered expression of TH receptors (TRs) underlying the evolution of accelerated metamorphosis in desert frogs. Frog metamorphosis is dependent on TH, and desert frog species have shorter larval periods compared to their non-desert relatives. Based on our preliminary data, it is hypothesized that desert species will have a more robust response to TH compared to non-desert species underlying their shorter larval period. Successful completion of this project will functionally test the effect of an evolutionary increase in TR expression on the rate of metamorphosis. The rationale for this research is that knowledge of how altered TR expression affects metamorphosis between frog species will advance our understanding of the developmental and evolutionary roles of this powerful hormone system. Integration of this research project with education will be accomplished by involving undergraduate and graduate students, not only in the research project, but also by enabling presentations of successful research at conferences. The current project enhances infrastructure for research and education through international collaborations and by providing educational material for undergraduate teaching. Results of the proposed research will be disseminated widely by publications in peer-reviewed journals and presentations at professional meetings, and all material used in the project will be deposited in research collections available for the scientific community. Finally, the research is expected to benefit society as a whole, primarily through bringing awareness to the general public of the underpinnings of evolution and biodiversity.