Biodemography and senescence in long-lived painted turtles

描述（由申请人提供）：我们为什么衰老？这个问题引起了许多人的兴趣，也许从我们这个物种的黎明开始。值得注意的是，最近对海龟的研究没有发现人口老化的证据，即没有死亡率和生殖老化。理论预测了衰老应该进化的环境，这意味着这种衰老可能是进化上不稳定的，它的发生依赖于环境。虽然理论上的预测已经在受控条件下的短寿命生物体中得到了证实，但我们对野生长寿生物体衰老的生态学和进化的理解仍然缺乏。此外，进化上保守的分子网络是一系列动物类群（果蝇、小鼠、蠕虫）衰老的基础。这些遗传和细胞机制是否以及如何在实验室模型领域之外成为死亡率和生殖衰老的基础仍然是未知的。量化衰老和特殊类群中这种衰老的进化、生态和生理决定因素，将对衰老的进化和持续性及其与其他生活史特征的共同调节产生有价值的见解。 我们将调查的进化，生态学和衰老的遗传学在一个野生种群的彩龟（picta），这已经详细研究了自1988年以来的关键方面。我们将回答以下问题。 1)做这些C。picta表现出与年龄相关的生殖能力下降和死亡率增加，这是衰老的证据？ 2)性别之间是否存在差异？早期经历对晚年死亡率和生育轨迹是否有长期影响？ 3)性别差异和早期生活对aing率的影响是否依赖于环境？ 4)后代的寿命是否与母亲的年龄或母亲和父亲的基因型正相关，从而表明寿命的遗传？ 5)年龄特异性生理特征（特别是基因表达和线粒体能量学）是否与哺乳动物和模型遗传生物相似，是死亡率和生殖轨迹的基础？ 我们将通过协调一致的实验和分析方法来解决这些问题。过去24年积累的现有信息学和基于收藏的资源，包括TurtleBase --一个包含与数百只海龟和海龟巢相对应的综合生态、环境、进化和遗传信息的数据库--将为分析管道提供输入，用于模拟衰老的生物人口学。重要的是，我们在地面上的海龟种群有已知年龄的个体，从孵化到最大寿命（约。25岁）。这些人的样本与我们存档的组织和DNA库相结合，将使我们能够独特地测试这些重要的问题。

DESCRIPTION (provided by applicant): Why do we senesce? This question has intrigued many, perhaps since the dawn of our species. Remarkably, recent work on turtles has detected no evidence of demographic senescence, i.e. - no mortality and reproductive aging. Theory predicts the circumstances under which aging should evolve, implying that such senescence may be evolutionarily labile and its occurrence context-dependent. While predictions from theory have been borne out in short-lived organisms under controlled conditions, our understanding of the ecology and evolution of senescence in long-lived organisms in the wild, where it evolved, is lacking. Moreover, evolutionarily conserved molecular networks underlie aging in a wide array of animal taxa (fruit flies, mice, nematode worms). Whether and how such genetic and cellular mechanisms underlie mortality and reproductive senescence outside of the realm of laboratory models remains unknown. Quantifying aging and the evolutionary, ecological, and physiological determinants of such senescence in exceptional taxa will yield valuable insights into the evolution and persistence of senescence, and its co-regulation with other life-history traits. We will investigate key aspects of the evolution, ecology and genetics of aging in a wild population of painted turtles (Chrysemys picta), which has been studied in detail since 1988. We will answer the following questions. 1) Do these C. picta exhibit age-related declines in reproduction and increases in mortality, which is evidence for senescence? 2) Are there differences between the sexes and are there long-lasting impacts of early- age experiences on late-life mortality and fertility trajectories? 3) Are sex differences and early-life impacts on aing rates context dependent? 4) Is offspring lifespan positively related to maternal age or maternal and paternal genotype, thereby suggesting the inheritance of lifespan? 5) Do age-specific physiological profiles (specifically, gene-expression and mitochondrial energetics) underlie mortality and reproduction trajectories similar to mammals and model genetic organisms? We will address these questions with coordinated experimental and analytical approaches. Existing informatics and collections-based resources accumulated over the past 24 yrs., including TurtleBase - a database comprising integrated ecological, environmental, evolutionary, and genetic information corresponding to hundreds of turtles and nests - will provide the input to an analytical pipeline for modeling the biodemography of aging. Importantly, our on-the-ground turtle population has individuals of known age ranging from hatchling to maximum lifespan (ca. 25 yrs.). Samples of these individuals combined with our archived tissue and DNA bank will be leveraged to render us uniquely able to test these important questions.