Zhang Bo, Feng Yidong, Lv Meiqi, Jia Lei, Liao Yongguan, Xu Xiaoyan, Meyer Axel, Sun Jinsheng, Fan Guangyi, Li Yumin, Zhang Yaolei, Zhao Na, Li Yunkai, Bao Baolong
International Research Center for Marine Biosciences, Ministry of Science and Technology, Shanghai Ocean University, Shanghai, 201306, China.
Southern Marine Science and Engineering Guangdong Laboratory-Zhanjiang, Zhanjiang, 524000, China.
Nat Commun. 2025 Aug 18;16(1):7684. doi: 10.1038/s41467-025-62544-w.
Cartilaginous fishes (e.g., sharks, rays, and skates) cannot see blue or violet light, potentially because they lack the shortwave-sensitive cone opsin gene (sws). Widespread gene loss can occur during evolution, but the evolutionary mechanisms underlying sws loss remains unclear. Here, we construct whole-genome assemblies of Okamejei kenojei (skate) and Prionace glauca (blue shark). We then analyze the distribution characteristics and intragroup differences of opsin-related genes in cartilaginous fishes. Using a zebrafish model with sws deleted we infer that in the presence of SWS1 and SWS2, blue and violet light respectively, can induce cell aging. This is followed by photoreceptor layer thinning, demonstrating, sws loss aids in preventing shortwave light damage to the eye. In the retinas of numerous cartilaginous fishes, the tapetum lucidum strongly reflects light. Therefore, in cartilaginous fish, the existence of tapetum lucidum in the retina and loss of sws may be interdependent; in other words, this adaptive gene loss may increase cartilaginous fish fitness.
软骨鱼类（如鲨鱼、鳐鱼和魟鱼）无法看见蓝色或紫色光，这可能是因为它们缺乏短波敏感视锥视蛋白基因（sws）。在进化过程中可能会发生广泛的基因丢失，但sws丢失背后的进化机制仍不清楚。在这里，我们构建了孔鳐和大青鲨的全基因组组装。然后，我们分析了软骨鱼类中视蛋白相关基因的分布特征和组内差异。使用缺失sws的斑马鱼模型，我们推断在分别存在SWS1和SWS2的情况下，蓝光和紫光可诱导细胞衰老。随后是感光层变薄，这表明，sws的丢失有助于防止短波光线对眼睛造成损伤。在许多软骨鱼类的视网膜中，反光层会强烈反射光线。因此，在软骨鱼类中，视网膜中反光层的存在和sws的丢失可能是相互依存的；换句话说，这种适应性基因丢失可能会提高软骨鱼类的适应性。
