Control of Breeding Cycles: Integration of Environmental Cues

脊椎动物有不同的生殖周期， 从短暂到漫长的繁殖季节，从精确的时间到 机会生殖期 时间上的变化 性腺成熟和繁殖的开始需要一个 种群或物种调节生殖激素的分泌， 响应环境信号。 温菲尔德博士提议 一个数学模型来描述一个给定的繁殖周期的类型， 人口 特别令人感兴趣的是恒定度和 在一个特定的繁殖周期内的偶然性。 越是坚定 在一个周期内（例如，环境处于有利于 繁殖的大部分时间），那么更少的环境信息是 需要调节生殖激素的分泌， 优化育种 随着周期中的偶然性增加（例如， 环境显示出重大变化，适合在一个 年），需要更多的环境线索来确定繁殖的开始时间。 PI选择了几种鸟类，它们具有不同程度的 恒定性和偶然性在他们的生殖周期，作为测试， 该模型 每个物种对环境信号的反应 已知会影响生殖功能（例如， 日照、温度、食物的可获得性）将被测试。 他们的 对性腺发育和生殖激素分泌的影响 将被衡量。 最终，这些环境因素的影响 大脑中荷尔蒙的基因表达， 环境和内部过程之间的关系，也将是 测定 这项研究的目的是探索一种 统一的理论，可用于预测如何所有脊椎动物（和 也许所有的有机体）整合来自环境的信号， 来优化繁殖。 也可能使用这种模式 用于繁殖以外的过程（例如迁移、生长等） 这项研究将提供新的见解的机制， 环境信号被转换成内部过程（例如 激素分泌）调节生殖功能。 这可能 对我们的生殖知识产生了相当大的影响， 可以为解决如何繁殖和 保护濒危物种和种群。

Vertebrates have diverse reproductive cycles spanning continua from brief to prolonged breeding seasons, and from precisely timed to opportunistic reproductive periods. Variations in the timing of gonadal maturation and onset of breeding require that individuals of a population or species adjust secretion of reproductive hormones in response to environmental signals. Dr. Wingfield proposes to develop a mathematical model to describe the type of breeding cycle for a given population. Of particular interest are the degrees of constancy and contingency within a particular breeding cycle. The more constancy within a cycle (e.g. the environment is in a state conducive to breeding most of the time), then less environmental information is required to regulate secretion of reproductive hormones and thus optimize breeding. As contingency in the cycle increases (e.g. the environment shows major changes in suitability for breeding within a year), more environmental cues are required to time onset of breeding. The PI has chosen several avian species, with varying degrees of constancy and contingency in their reproductive cycles, as tests of this model. The responses of each species to environmental signals known to influence reproductive function (e.g. annual change in daylength, temperature, availability of food) will be tested. Their effects on gonadal development, and secretion of reproductive hormones will be measured. Ultimately, the effects of these environmental cues on gene expression for hormones within the brain, that act as a link between the environmental and internal processes, will also be determined. The proposed research is designed to explore the possibility of a unifying theory that can be used to predict how all vertebrates (and perhaps all organisms) integrate signals from the environment in order to optimize reproduction. It may also be possible to use this model for processes other than reproduction (e.g. migration, growth etc.) The research will provide new insight into the mechanisms by which environmental signals are transduced into internal processes (such as hormone secretion) that regulate reproductive function. This may have considerable impact on our knowledge of reproduction in general, and could provide a firm base for approaching problems of how to breed and protect endangered species and populations.