COLLABORATIVE RESEARCH: Neuroendocrine basis of gestural display evolution

动物用于生殖交流的信号对于生存和后代至关重要，因此此类信号的进化得到了广泛的研究。 然而，尽管有这项工作，从生理学的角度对信号进化知之甚少，特别是关于神经系统如何改变以支持新信号的出现。为了解决这一问题，本研究项目调查了青蛙中一种不寻常的生殖通讯信号的机制，这种信号被称为“脚旗”。“通过比较雄激素，如睾酮，如何作用于脊髓和后肢肌肉在foot-flagging与非foot-flagging青蛙，该项目旨在了解发生了什么变化，因为foot-flagging在这个物种组中进化。 该项目还将解释运动疾病的生理模型应用于理解这种复杂的生态相关行为的演变。 结果提供了关于神经系统如何在自然环境中进化和发挥作用的见解。 此外，女子学院，研究型大学和世界级维也纳动物园的研究人员之间的独特合作为第一和第二年的本科生，特别是女性和第一代大学生提供了实践研究经验。 研究人员还将这项研究纳入本科课程，并资助国际研究经验，包括在婆罗洲、印度和秘鲁开展的有关踏足蛙生物学和保护的公共宣传活动。该项目采用比较方法，结合分子和行为分析，测试雄激素的作用如何在神经运动系统中被修改，以支持新的生殖通信信号的进化。先前的数据显示，雄性青蛙出现“脚下垂”--一种通过明显地挥动后肢产生的信号--其特征是控制这种运动的骨骼肌内的雄激素敏感性增加了10倍。使用定量实时PCR和原位杂交来比较雄激素受体水平在足下垂与非足下垂物种，本研究项目测试的假设，即在表达水平的变化和模式的雄激素受体在多个水平的后肢神经运动通路与足下垂在多个青蛙谱系的独立进化。此外，该项目使用药理学工具来阻断雄激素受体，以测试腿部肌肉中的雄激素信号传导是足下垂行为所需的假设，并支持控制后肢运动的脊髓运动回路。虽然在运动疾病的研究中报道了这种神经运动回路的“自下而上”的改变，但该项目是第一个探索这种改变作为调节复杂的生态相关运动行为的机制的研究。

The signals that animals use for reproductive communication are vital for survival and progeny, and thus the evolution of such signals is extensively studied. Yet, despite this work, little is known about signal evolution from a physiological perspective, particularly with respect to how the nervous system is changed to support the emergence of novel signals. To address this issue, this research project investigates the mechanisms underlying an unusual reproductive communication signal in frogs, known as the "foot flag." By comparing how androgenic hormones, such as testosterone, act on the spinal cord and hind limb muscles in foot-flagging vs. non foot-flagging frogs, this project aims to understand what changes occurred as foot-flagging evolved in this species group. This project also applies physiological models that have explained motor disease to understanding the evolution of this complex and ecologically relevant behavior. Results provide insight into how neural systems can evolve and function in the natural environment. Additionally, the unique collaboration between researchers at a women's college, a research university, and the world-class Vienna Zoo provide hands-on research experiences for 1st and 2nd year undergraduates, particularly women and first-generation college students. The investigators also incorporate this research into undergraduate courses and fund international research experiences that include public outreach about the biology and conservation of foot-flagging frogs in Borneo, India, and Peru.This project uses a comparative approach and combines molecular and behavioral analyses to test how the action of androgenic hormones is modified in neuromotor systems to support the evolution of new reproductive communication signals. Prior data shows that the emergence of "foot flagging" in male frogs - a signal that is produced by conspicuously waving the hind limb - is marked by a 10-fold increase in the androgenic sensitivity within the skeletal muscles that control this movement. Using quantitative real-time PCR and in situ hybridization to compare androgen receptor levels in foot-flagging vs. non-foot flagging species, this research project tests the hypothesis that changes in expression levels and patterning of androgen receptors within multiple levels of the hindlimb neuromotor pathway are associated with the independent evolution of foot flagging in multiple frog lineages. Furthermore, this project uses pharmacological tools to block androgen receptors in order to test the hypothesis that androgenic signaling in leg muscles is required for foot-flagging behavior and to support the spinal motor circuitry that controls hind limb movement. Though such "bottom up" modification of neuromotor circuitry is reported in studies of motor disease, this project is the first study to explore this as a mechanism for regulating a complex and ecologically relevant motor behavior.