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DISSERTATION RESEARCH: The Evolution of Crocodylian Cranial Development

论文研究：鳄鱼颅骨发育的进化

基本信息

批准号：
1701745
负责人：
Stephanie E Pierce
金额：
$ 2.2万
依托单位：
Harvard University
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2017
资助国家：
美国
起止时间：
2017-06-01 至 2020-05-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1701745&HistoricalAwards=false
关键词：
DISSERTATION RESEARCH Evolution Crocodylian Cranial

项目摘要

Crocodylians (crocodiles and alligators), often labeled 'living fossils, are commonly thought to have an ancient and conservative skeletal anatomy and lifestyle. However, modern crocodylians are more diverse than often appreciated and their skulls, in particular, can range from short and wide to incredibly long and slender. Prior research has shown that crocodylian skull shape is correlated with dietary and habitat specializations, but it remains unclear how these shapes come to be. The formation of crocodylian skull diversity is tied to development: the changes that occur in an individual as it grows from a fertilized egg to an adult. The process of development is controlled by genes, and changes to how genes are expressed can modify developmental pathways and adult anatomy. By combining data from fossils, crocodylian embryos, and modern developmental biology techniques, this project will reveal which changes in developmental pathways were key to the evolution of the crocodylian skull, and the evolutionary diversity of crocodylians. Insights from this research may also inform general connections between genomic, developmental and organismal complexity in vertebrates. To capitalize on the public interest in crocodiles and their relatives (dinosaurs and birds), this project will develop K-12 activities for students and teachers in conjunction with the Harvard Museum of Natural History (HMNH). These activities explore key concepts in paleontology and developmental biology and will be tied to the Next Generation Science Standards. The HMNH provides a unique venue to reach a diverse urban audience from across the Boston Metropolitan area and visitors from around the world. Unique morphological features distinguish major groups of animals like crocodylians, mammals, and birds. These features are important for the particular lifestyles and habits of these groups and have been critical for their survival over millions of years. The formation of this diversity is caused by the evolution of novel genes, novel functions for genes, or modification to the developmental pattern of gene expression. Integrating fossils, embryos, and developmental genetic techniques, this study will reveal developmental mechanisms involved in the evolution of crocodylian cranial diversity. This project will study the expression patterns of key genes involved in the development of the skull in extant crocodylians using in situ hybridization. Developmental stages from eight target species, which broadly sample the phylogeny and diversity of snout shapes in modern crocodylians, will be analyzed. The project aims to experimentally replicate ancestral and derived gene expression patterns and to use geometric morphometrics to quantify the relationship between expression patterns and skull shapes. These functional studies in alligator embryos will test the likelihood that particular changes in development were the cause of evolutionary changes in anatomy. This project integrates paleontology, anatomy, and developmental biology to link changes in anatomy to genetic inheritance through development. This integrative methodology will lead to a greater understanding of critical mechanisms underlying the evolution of anatomical diversity and novel features of organisms.

鳄鱼（鳄鱼和短吻鳄），通常被称为“活化石”，通常被认为具有古老而保守的骨骼解剖学和生活方式。然而，现代鳄鱼比通常所欣赏的更多样化，特别是它们的头骨，可以从短而宽到令人难以置信的长而细。先前的研究表明，鳄鱼的头骨形状与饮食和栖息地的专门化有关，但目前还不清楚这些形状是如何形成的。鳄鱼头骨多样性的形成与发育有关：个体从受精卵到成年人的变化。发育过程由基因控制，基因表达方式的改变可以改变发育途径和成人解剖学。通过结合化石，鳄鱼胚胎和现代发育生物学技术的数据，该项目将揭示发育途径的哪些变化是鳄鱼头骨进化的关键，以及鳄鱼的进化多样性。这项研究的见解也可能为脊椎动物的基因组，发育和有机体复杂性之间的一般联系提供信息。为了利用公众对鳄鱼及其亲属（恐龙和鸟类）的兴趣，该项目将与哈佛自然历史博物馆（HMNH）合作，为学生和教师开发K-12活动。这些活动探索古生物学和发育生物学的关键概念，并将与下一代科学标准联系在一起。HMNH提供了一个独特的场所，可以接触到来自波士顿大都会区的各种城市观众和来自世界各地的游客。独特的形态特征区分了鳄鱼、哺乳动物和鸟类等主要动物群体。这些特征对于这些群体的特定生活方式和习惯非常重要，并且对于他们数百万年的生存至关重要。这种多样性的形成是由新基因的进化、基因的新功能或基因表达的发育模式的改变引起的。结合化石、胚胎和发育遗传学技术，本研究将揭示鳄类颅骨多样性演化的发育机制。本计画将利用原位杂交技术研究现存鳄鱼头骨发育过程中关键基因的表达模式。将分析八个目标物种的发育阶段，这些目标物种广泛地采样了现代鳄鱼的吻部形状的发育和多样性。该项目旨在通过实验复制祖先和衍生的基因表达模式，并使用几何形态测量学来量化表达模式和头骨形状之间的关系。这些对短吻鳄胚胎的功能研究将测试发育中的特定变化是解剖学进化变化的原因的可能性。该项目整合了古生物学，解剖学和发育生物学，将解剖学的变化与发育过程中的遗传遗传联系起来。这种综合方法将导致更好地了解生物体的解剖多样性和新特征的演变背后的关键机制。