Dissertation Research: Developmental Maintenance of Evolutionary Conservatism: A Comparative and Experimental Analysis of Sphenoid Skeletogenesis in Birds and Mammals

形态守恒的基本机制尚不清楚。虽然一些解剖区域经历了重大的进化转变，但其他区域却不愿改变。在五亿年的进化过程中，尽管头骨的其他部分发生了许多变化，但椎骨头部的一部分，即蝶骨区域，结构之间的关系一直保持不变。经典的比较解剖学和现代的分子和细胞方法相结合，研究了蝶骨骨架的形态发生过程，并描述了可能使该区域在脊椎动物中进化保护的发育特性。提出了两项补充研究。第一种方法确定了在蝶骨骨架形成过程中重要的特定元素。先前进行的实验，如基因敲除、手术操作和致畸剂治疗进行了分析，以产生数据如何干扰神经管、脊索、三叉神经和垂体影响蝶骨具有固有的模式信息。这涉及到新的神经嵴和中胚层细胞的实验性移植。这项研究1)提供了形态发生事件如何影响骨骼模式的理解，2)为复杂颅骨结构的整合提供了新的见解，3)为形态学进化中发育相互作用的研究提供了重要的例子。

Smith 9701104 Basic mechanisms underlying morphological conservation are not well understood. While some anatomical regions undergo major evolutionary transformations, others are resistant to change. The relations among structures in one part of the vertebrae head, the sphenoid region, have remained constant during five hundred million years of evolution despite numerous modifications in other parts of the skull. Classical comparative anatomy and contemporary molecular and cellular approaches are combined to investigate morphogenetic processes involved in pattering the sphenoid skeleton and t characterize developmental properties that may enable evolutionary conservation of this region across vertebrates. Two complementary studies are proposed. The first identifies specific elements that are important in pattering the sphenoid skeleton. Previously performed experiments such as gene knockouts, surgical manipulations, and teratogen treatments are analyzed to generate data on how perturbations to the neural tube, notochord, trigeminal nerve, and pituitary gland affect the sphenoid skeleton possess intrinsic patterning information. This involves new experimental transplantations of neural crest and mesodermal cells. This investigation 1) provides and understanding of how morphogenetic events affect skeletal patterning, 2) gives new insights on the integration of complex cranial structures, and 3) contributes important examples to the study of developmental interactions in morphological evolution.