Dissertation Research: Integrative Study of the Evolution of Squamate Limb Reduction

PI：Crompton 9801134 陆生脊椎动物（四足动物）的肢体减少是一种常见现象。有些谱系会减少四肢的总尺寸或完全失去它们，而另一些则只是减少骨骼的总数（两栖动物只有四个手指，鸟类只有三个）。尽管四足动物的肢体减少很常见，但这种现象背后的进化和发育机制却知之甚少。 本研究将采取综合的方法来理解的形态，分子和功能方面的肢体减少，通过澳大利亚蜥蜴Hemiergis。Hemiergis是一个理想的模式生物肢体还原研究，因为它具有梯度的数字配置（从5个手指和脚趾到2个手指和脚趾）在一个属的几个密切相关的物种。本研究旨在比较不同种类的Hemiergis的骨骼发育模式，追踪肢体模式基因表达的变化，并记录伴随肢体减少的功能变化。肢体减少通常涉及一个共同的顺序的数字损失，和Hemiergis发展的研究将提供深入了解的情况下，肢体减少在其他四足动物群体。 这个项目也将阐明特定基因在胚胎肢体形成中的进化作用。

PI: Crompton 9801134 Limb reduction in terrestrial vertebrates (tetrapods) is a common phenomenon. Some lineages reduce the total size of their limbs or lose them altogether, while others simply reduce the total number of bones (amphibians have only four fingers and birds have only three). Despite the common occurrence of limb reduction in tetrapods, the evolutionary and developmental mechanisms underlying this phenomenon are poorly understood. This study will take an integrative approach to understanding the morphological, molecular, and functional aspects of limb reduction through the Australian lizard Hemiergis. Hemiergis is an ideal model organism for limb reduction studies because it features a gradient of digit configurations (from 5 fingers and toes to 2 fingers and toes) within a genus of several closely related species. This investigation endeavors to compare patterns of skeletal development in different species of Hemiergis, trace changes in the expression of limb patterning genes, and document the functional changes that accompany limb reduction. Limb reduction typically involves a common order of digit loss, and studies of Hemiergis development will provide insight into cases of limb reduction in other tetrapod groups. This project will also elucidate the evolutionary role of specific genes in patterrdng the embryonic limb.