Evolution of development among gastropod molluscs

腹足类软体动物的发育演变

• 批准号: 138169-2009
• 负责人: Page, Louise
• 金额: $ 2.55万
• 依托单位: University of Victoria
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2014
• 资助国家: 加拿大
• 起止时间: 2014-01-01 至 2015-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=545494
• 关键词: Evolution; development; among; gastropod; molluscs

Rudyard Kipling's Just So Stories have an enduring appeal because of our inherent fascination with bizarre features of animals and plants and our desire to know where they came from. How did flies get their wings? How did birds get their feathers? Interest in novel features of organisms is not only the stuff of quaint entertainments. Questions that ask how an organism acquired a feature that is obviously not present in otherwise similar organisms are of central importance to evolutionary biology. Novelties perplex biologists because, if natural selection works by modifying pre-existing structures, then how do seemingly new characteristics come into being in the first place? The need to explain morphological novelties has been a major impetus for bringing developmental biology back within the embrace of evolutionary biology. Biologists now recognize that small changes during the development of an organism, such as when a structure starts to form, can become magnified into large differences in the fully formed organism. I use gastropod mollusks as a model to study the development of novelties within this hugely diverse group of animals. I am investigating a hypothesis that may explain the highly contorted body plan of gastropods. Comparative studies of gastropod development suggest that the contorsion may have originated as an asymmetry in the development of the two sides of the body. I also seek to explain how predatory gastropods were able to evolve extraordinarily specialized feeding structures without compromising feeding activities of the larval stage. This issue has wide significance because most of the major groups of animals are invertebrates and their bodies are built within a life cycle that includes a larval stage. Needs of the larva may limit possibilities for adult evolution. Finally, I ask how swimming larvae of gastropods acquired the ability to feed and grow prior to metamorphosis. To study these questions, my students and I culture a wide variety of marine gastropods and we use various techniques for morphological analysis, such as scanning and transmission electron microscopy, computer-assisted 3D reconstruction of sectioned material, and immunolabeling to highlight structures and cells of interest.

拉迪亚德·吉卜林的《原来如此的故事》之所以具有持久的吸引力，是因为我们对动植物的奇异特征有着与生俱来的迷恋，并且渴望知道它们来自哪里。苍蝇是怎么长出翅膀的？鸟类是如何获得羽毛的？对生物体新奇特征的兴趣不仅仅是古雅娱乐的内容。询问有机体如何获得在其他类似有机体中明显不存在的特征的问题对于进化生物学至关重要。新颖性让生物学家感到困惑，因为如果自然选择是通过改变预先存在的结构来发挥作用，那么看似新的特征最初是如何形成的呢？解释形态学新颖性的需要一直是将发育生物学带回进化生物学怀抱的主要推动力。生物学家现在认识到，生物体发育过程中的微小变化，例如结构开始形成时，可能会放大为完全形成的生物体的巨大差异。我使用腹足类软体动物作为模型来研究这个极其多样化的动物群体中新奇事物的发展。我正在研究一个可能解释腹足动物高度扭曲的身体结构的假设。腹足动物发育的比较研究表明，这种扭曲可能起源于身体两侧发育的不对称。我还试图解释捕食性腹足动物如何能够在不影响幼虫阶段摄食活动的情况下进化出非常专业的摄食结构。这个问题具有广泛的意义，因为大多数主要动物类群都是无脊椎动物，它们的身体是在包括幼虫阶段的生命周期内构建的。幼虫的需求可能会限制成虫进化的可能性。最后，我问游泳的腹足动物幼虫如何在变态之前获得进食和生长的能力。为了研究这些问题，我和我的学生培养了各种各样的海洋腹足动物，并使用各种技术进行形态分析，例如扫描和透射电子显微镜、计算机辅助切片材料的 3D 重建以及免疫标记以突出显示感兴趣的结构和细胞。