Department of Systems Biology, Harvard Medical School, Boston, MA, United States.
Department of Biology, Georgetown University, Washington, DC, United States.
Curr Top Dev Biol. 2022;147:545-562. doi: 10.1016/bs.ctdb.2022.01.004. Epub 2022 Mar 1.
Hemichordates have long been recognized as a critical group for addressing hypotheses of chordate origins. Historically this was due to anatomical traits that resembled those of chordates, most strikingly the dorsolateral gill slits. As molecular data and phylogenetic analyses were found to support a close phylogenetic relationship between hemichordates and chordates within the deuterostomes, interest was revived in hemichordates. In particular, Saccoglossus kowalevskii has been developed as a molecular model to represent hemichordate developmental biology. Herein, we highlight the considerations when choosing a particular species to study and the challenges we encountered when developing S. kowalevskii. We discuss our findings and how method and tool development enabled them, and how we envision expanding our repertoire of molecular tools in the future. Establishing a new model organism comes with many obstacles-from identifying a reliable season to collect animals, to developing modern molecular techniques. The Saccoglossus research community has benefited greatly from the collaborations and teamwork established over the years. As a result, Saccoglossus is well positioned to contribute to a new century of evolutionary developmental (evo-devo) research.
半索动物长期以来被认为是解决脊索动物起源假说的关键群体。历史上，这是由于其解剖学特征与脊索动物相似，最显著的是背外侧鳃裂。随着分子数据和系统发育分析发现半索动物和后口动物中的脊索动物之间存在密切的系统发育关系，对半索动物的兴趣又重新燃起。特别是，食蛞蝓被开发为代表半索动物发育生物学的分子模型。本文重点介绍了选择特定物种进行研究时需要考虑的因素，以及在开发食蛞蝓时遇到的挑战。我们讨论了我们的发现以及方法和工具的开发如何使这些发现成为可能，以及我们如何设想在未来扩展我们的分子工具库。建立一个新的模式生物面临着许多障碍——从确定一个可靠的季节来收集动物，到开发现代分子技术。食蛞蝓研究社区多年来的合作和团队合作受益匪浅。因此，食蛞蝓很有希望为新的进化发育（evo-devo）研究做出贡献。
