Phillips Genevieve A C, Carleton Karen L, Marshall N Justin
Queensland Brain Institute, The University of Queensland, Brisbane, QLD, Australia
Department of Biology, University of Maryland, College Park.
Mol Biol Evol. 2016 Jan;33(1):201-15. doi: 10.1093/molbev/msv213. Epub 2015 Oct 12.
Coral reefs are one of the most spectrally diverse environments, both in terms of habitat and animal color. Species identity, sex, and camouflage are drivers of the phenotypic diversity seen in coral reef fishes, but how the phenotypic diversity is reflected in the genotype remains to be answered. The labrids are a large, polyphyletic family of coral reef fishes that display a diverse range of colors, including developmental color morphs and extensive behavioral ecologies. Here, we assess the opsin sequence and expression diversity among labrids from the Great Barrier Reef, Australia. We found that labrids express a diverse palette of visual opsins, with gene duplications in both RH2 and LWS genes. The majority of opsins expressed were within the mid-to-long wavelength sensitive classes (RH2 and LWS). Three of the labrid species expressed SWS1 (ultra-violet sensitive) opsins with the majority expressing the violet-sensitive SWS2B gene and none expressing SWS2A. We used knowledge about spectral tuning sites to calculate approximate spectral sensitivities (λmax) for individual species' visual pigments, which corresponded well with previously published λmax values for closely related species (SWS1: 356-370 nm; SWS2B: 421-451 nm; RH2B: 452-492 nm; RH2A: 516-528 nm; LWS1: 554-555 nm; LWS2: 561-562 nm). In contrast to the phenotypic diversity displayed via color patterns and feeding ecology, there was little amino acid diversity within the known opsin sequence tuning sites. However, gene duplications and differential expression provide alternative mechanisms for tuning visual pigments, resulting in variable visual sensitivities among labrid species.
珊瑚礁是栖息地和动物颜色方面光谱多样性最高的环境之一。物种身份、性别和伪装是珊瑚礁鱼类表型多样性的驱动因素，但这种表型多样性如何在基因型中体现仍有待解答。隆头鱼科是一个大型的多系珊瑚礁鱼类家族，它们呈现出各种各样的颜色，包括发育过程中的颜色变体和广泛的行为生态学特征。在这里，我们评估了来自澳大利亚大堡礁的隆头鱼科鱼类视蛋白序列和表达的多样性。我们发现隆头鱼科鱼类表达了多种视觉视蛋白，其中RH2和LWS基因都存在基因重复。所表达的大多数视蛋白属于中长波长敏感类别（RH2和LWS）。三种隆头鱼科物种表达了SWS1（紫外敏感）视蛋白，大多数表达了对紫光敏感的SWS2B基因，没有一个表达SWS2A。我们利用有关光谱调谐位点的知识来计算各个物种视觉色素的近似光谱敏感度（λmax），这与先前发表的密切相关物种的λmax值非常吻合（SWS1：356 - 370纳米；SWS2B：421 - 451纳米；RH2B：452 - 492纳米；RH2A：516 - 528纳米；LWS1：554 - 555纳米；LWS2：561 - 562纳米）。与通过颜色模式和摄食生态学表现出的表型多样性形成对比的是，在已知的视蛋白序列调谐位点内氨基酸多样性很少。然而，基因重复和差异表达为调节视觉色素提供了替代机制，导致隆头鱼科物种之间视觉敏感度存在差异。
