School of Biological Sciences, The University of Queensland, Brisbane, Queensland, Australia.
Queensland Brain Institute, The University of Queensland, Brisbane, Queensland, Australia.
Genome Biol Evol. 2021 Oct 1;13(10). doi: 10.1093/gbe/evab184.
Many animals including birds, reptiles, insects, and teleost fishes can see ultraviolet (UV) light (shorter than 400 nm), which has functional importance for foraging and communication. For coral reef fishes, shallow reef environments transmit a broad spectrum of light, rich in UV, driving the evolution of diverse spectral sensitivities. However, the identities and sites of the specific visual genes that underly vision in reef fishes remain elusive and are useful in determining how evolution has tuned vision to suit life on the reef. We investigated the visual systems of 11 anemonefish (Amphiprioninae) species, specifically probing for the molecular pathways that facilitate UV-sensitivity. Searching the genomes of anemonefishes, we identified a total of eight functional opsin genes from all five vertebrate visual opsin subfamilies. We found rare instances of teleost UV-sensitive SWS1 opsin gene duplications that produced two functionally coding paralogs (SWS1α and SWS1β) and a pseudogene. We also found separate green sensitive RH2A opsin gene duplicates not yet reported in the family Pomacentridae. Transcriptome analysis revealed false clown anemonefish (Amphiprion ocellaris) expressed one rod opsin (RH1) and six cone opsins (SWS1β, SWS2B, RH2B, RH2A-1, RH2A-2, LWS) in the retina. Fluorescent in situ hybridization highlighted the (co-)expression of SWS1β with SWS2B in single cones, and either RH2B, RH2A, or RH2A together with LWS in different members of double cone photoreceptors (two single cones fused together). Our study provides the first in-depth characterization of visual opsin genes found in anemonefishes and provides a useful basis for the further study of UV-vision in reef fishes.
许多动物，包括鸟类、爬行动物、昆虫和硬骨鱼，都能看到紫外线（UV）光（短于 400nm），这对觅食和交流具有重要的功能意义。对于珊瑚礁鱼类来说，浅礁环境传输的光谱范围很广，富含紫外线，这推动了它们多样化光谱敏感性的进化。然而，珊瑚礁鱼类视觉的具体视觉基因的身份和位置仍然难以捉摸，对于确定进化如何调整视觉以适应珊瑚礁生活是有用的。我们研究了 11 种海葵鱼（Amphiprioninae）物种的视觉系统，特别是探究了促进 UV 敏感性的分子途径。通过搜索海葵鱼的基因组，我们从所有五个脊椎动物视觉视蛋白亚家族中总共鉴定出了 8 个功能性视蛋白基因。我们发现了罕见的硬骨鱼 UV 敏感 SWS1 视蛋白基因重复的例子，这些重复产生了两个功能编码的同源物（SWS1α 和 SWS1β）和一个假基因。我们还发现了在 Pomacentridae 家族中尚未报道的单独的绿色敏感 RH2A 视蛋白基因重复。转录组分析显示，假小丑海葵鱼（Amphiprion ocellaris）在视网膜中表达了一个视杆蛋白（RH1）和六个视锥蛋白（SWS1β、SWS2B、RH2B、RH2A-1、RH2A-2、LWS）。荧光原位杂交突出显示了 SWS1β 与单锥细胞中的 SWS2B 的（共）表达，以及 RH2B、RH2A 或 RH2A 与双锥细胞感光器（两个单锥细胞融合在一起）中的 LWS 一起表达。我们的研究首次深入描述了海葵鱼中发现的视觉视蛋白基因，并为进一步研究珊瑚礁鱼类的 UV 视觉提供了有用的基础。
