Temporal profiling and functional analysis of temperature-dependent gonad determination

性腺决定是个体作为男性或女性启动发育的过程，由许多机制控制。在哺乳动物中，包括人类在内，基因决定对温度和外部激素等环境影响不敏感，而是对Y染色体上的显性遗传开关做出反应，即Y染色体上的个体变成雄性，而没有Y的个体变成雌性。其他脊椎动物，如鳄鱼和许多海龟，对非遗传影响很敏感，如卵孵化温度。在这些物种中，性腺的遗传决定因素尚不清楚，对温度或其他环境信号如何影响性腺决定也知之甚少。该项目的目标是确定在脊椎动物物种中支配性腺决定的共同原则。利用在老鼠身上开发的方法，将进行实验，以确定温度诱导的启动乌龟雄性和雌性发育的顺序基因表达事件，并识别乌龟和老鼠之间的相似和不同之处。在雄性和雌性产卵温度之间的中点孵化海龟卵的初步结果表明，在海龟中存在另一个与温度无关的潜在机制来确定性腺。这个项目将描述这一额外的途径，准确地确定温度何时以及如何影响结果，并提供大量对这一领域和其他领域有价值的序列和表达数据。这项工作为杜克大学的研究生和本科生以及北卡罗来纳科学与数学学院的来访高中生提供了一个很好的机会来培训进化和发育生物学。将特别重视在夏季海龟季节介绍年轻学生，包括来自代表人数不足的群体的学生参加实地工作。此外，我们计划利用这个项目，通过达勒姆的科学咖啡馆，让公众参与有关基础科学、环境影响和保护的对话，从而促进科学素养。

Gonad determination, the process by which an individual initiates development as a male or female, is controlled by many mechanisms. In mammals, including humans, genad determination is insensitive to environmental influences like temperature and external hormones, but instead is responsive to a dominant genetic switch on the Y chromosome, such that individuals with a Y become males and those without a Y become females. Other vertebrates such as alligators and many turtles, are sensitive to non-genetic influences such as egg incubation temperature. In these species, no genetic determinant of gonads is known, and little is known about how temperature or other environmental signals influence gonad determination. The goal of this project is to identify common principles that govern gonad determination across vertebrate species. Using methods developed with mice, experiments will be carried out to determine the sequential gene expression events induced by temperature that initiate male and female development in turtles, and to identify the similarities and differences between turtles and mice. Preliminary results from incubating turtle eggs at the midpoint between male- and female-producing temperatures suggest that an additional underlying temperature-independent mechanism exists for determining gonads exists in turtles. This project will characterize this additional pathway, pinpoint when and how temperature influences the outcome, and provide large quantities of sequence and expression data valuable to this and other fields.This work provides an outstanding opportunity for training in evolutionary and developmental biology for Duke graduate and undergraduate students, and visiting high school students from the North Carolina School for Science and Math. Special emphasis will be placed on introducing young students, including those from underrepresented groups, to field work during the summer turtle season. In addition, we plan to use this project to stimulate scientific literacy by engaging the public in conversations about basic science, the impact of the environment, and conservation via the Science Café in Durham.