Authors: Danielle M. DeLeo, Manabu Bessho-Uehara, Steven H.D. Haddock, Catherine S. McFadden, and Andrea M. Quattrini
Journal: Proceedings of the Royal Society B: Biological Sciences
Bioluminescence is a widespread phenomenon that has evolved multiple times across the tree of life, converging among diverse fauna and habitat types. The ubiquity of bioluminescence, particularly in marine environments where it is commonly used for communication and defense, highlights the adaptive value of this trait, though the evolutionary origins and timing of emergence remain elusive for a majority of luminous organisms. Anthozoan cnidarians are a diverse group of animals with numerous bioluminescent species found throughout the world's oceans, from shallow waters to the light-limited deep sea where bioluminescence is particularly prominent. This study documents the presence of bioluminescent Anthozoa across depth and explores the diversity and evolutionary origins of bioluminescence among Octocorallia—a major anthozoan group of marine luminous organisms. Using a phylogenomic approach and ancestral state reconstruction, we provide evidence for a single origin of bioluminescence in Octocorallia and infer the age of occurrence to around the Cambrian era, approximately 540 Ma—setting a new record for the earliest timing of emergence of bioluminescence in the marine environment. Our results further suggest this trait was largely maintained in descendants of a deep-water ancestor and bioluminescent capabilities may have facilitated anthozoan diversification in the deep sea.
生物发光是一种广泛存在的现象，在生命之树上已经演化了多次，在不同的动物群和生境类型中趋于一致。生物发光无处不在，尤其是在海洋环境中，生物发光通常被用于交流和防御，突显了这一特性的适应性价值，尽管多数发光生物的进化起源和出现时间仍然难以确定。刺细胞动物门珊瑚虫纲是一个多样化的动物群体，其生物发光物种遍布世界各大洋，从浅海到光照受限、生物发光现象尤为突出的深海。本研究记录了不同深度生物发光珊瑚虫的存在，并探讨了八放珊瑚——一种主要的海洋发光生物的多样性和进化起源。利用系统基因组学方法和祖先性状重建，本文提供了八放珊瑚生物发光单一起源的证据，并推断出其发生年龄大约在寒武纪，约540 Ma，创下了海洋环境中生物发光最早出现时间的新记录。本文结果进一步表明，这一特征在深海祖先的后代中被很大程度上保留了下来，并且生物发光能力可能促进了深海中珊瑚虫的多样化。
（实习生郑好编译）
