Temporal profiling and functional analysis of temperature-dependent gonad determination

性腺决定，即个体开始发育为男性或女性的过程，是由许多机制控制的。在包括人类在内的哺乳动物中，性别决定对温度和外部激素等环境影响不敏感，而是对Y染色体上的显性基因开关做出反应，因此有Y染色体的个体成为雄性，没有Y染色体的个体成为雌性。其他脊椎动物，如短吻鳄和许多海龟，对卵孵化温度等非遗传影响很敏感。在这些物种中，性腺的遗传决定因素是未知的，对于温度或其他环境信号如何影响性腺的决定也知之甚少。这个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。利用在小鼠身上开发的方法，将进行实验，以确定温度诱导的启动海龟雄性和雌性发育的顺序基因表达事件，并确定海龟和小鼠之间的异同。在雄性和雌性产卵温度之间的中点孵化海龟蛋的初步结果表明，存在一个额外的潜在的温度无关机制来决定海龟的性腺是否存在。该项目将描述这一额外的途径，确定温度何时以及如何影响结果，并提供大量对该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来访的北卡罗来纳科学与数学学院的高中生提供了一个很好的进化和发育生物学培训机会。将特别强调介绍年轻学生，包括来自代表性不足群体的学生，在夏季海龟季节进行实地工作。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，从而激发科学素养。

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.