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: 2010
• 资助国家: 加拿大
• 起止时间: 2010-01-01 至 2011-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=451775
• 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.

鲁德亚德·吉卜林（Rudyard Kipling）的故事具有持久的吸引力，因为我们对动物和植物的奇异特征的固有着迷，以及我们渴望知道它们的来源。苍蝇是如何得到翅膀的？鸟是如何得到羽毛的？对生物的新颖特征的兴趣不仅是古朴的娱乐活动。询问有机体如何获得显然在其他类似生物中不存在的特征的问题对进化生物学至关重要。新颖性使生物学家感到困惑，因为，如果自然选择通过修改预先存在的结构来起作用，那么看似新的特征如何首先出现？解释形态新颖性的需求一直是使发展生物学重回进化生物学的主要动力。生物学家现在认识到，在生物体的发展过程中，例如结构开始形成时，可能会变成完全形成的生物体的巨大差异。我使用腹足动物软体动物作为模型来研究这种多样化的动物群体中新颖性的发展。我正在研究一个假设，该假设可能解释了高度扭曲的腹足动物计划。腹足动物发育的比较研究表明，这种偏变可能起源于人体双方发展中的不对称性。我还试图解释掠食性腹足类动物如何能够在不损害幼体阶段的喂养活动的情况下发展出非常专业的喂养结构。这个问题具有广泛的意义，因为大多数主要动物都是无脊椎动物，它们的身体建立在包括幼虫阶段的生命周期之内。幼虫的需求可能会限制成人进化的可能性。最后，我问腹足动物的游泳幼虫是如何在变形之前获得喂养和生长的能力的。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类动物，我们使用各种技术进行形态学分析，例如扫描和传输电子显微镜，计算机辅助的分割材料的3D重建以及免疫标记来突出感兴趣的结构和细胞。