Molecular evolution of arthropod color vision deduced from multiple opsin genes of jumping spiders
Molecular evolution of arthropod color vision deduced from multiple opsin genes of jumping spiders
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DOI：
10.1007/s00239-008-9065-9
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发表时间：
2008-02-01
影响因子：
3.9
通讯作者：
Tokunaga, Fumio
中科院分区：
文献类型：
--
作者：
Koyanagi, Mitsumasa;Nagata, Takashi;Tokunaga, Fumio
在陆生动物中，只有脊椎动物和节肢动物具有波长辨别能力，即所谓的“色觉”。为了使色觉存在，需要多种视蛋白，这些视蛋白编码对不同波长的光敏感的视色素。虽然脊椎动物中视蛋白的分子进化已经得到很好的研究，但节肢动物中的视蛋白仍有待阐明。这主要是由于非昆虫节肢动物的视蛋白基因的信息不足。为了了解节肢动物色觉进化的概况，我们从两种跳蛛（Hasariusadansoni和Plexippuspaykulli）中分离了三种视蛋白Rh 1、Rh 2和Rh 3。这些蜘蛛属于螯肢类，这是离六足纲（昆虫）最远的类群之一，它们和昆虫一样有色觉。跳蛛视蛋白的系统发育分析揭示了节肢动物色觉进化的一个生与死的过程。跳蛛视蛋白的系统发育位置显示，至少有三个视蛋白已经存在之前，螯肢-Pancrustacea分裂。此外，跳蛛Rh 3和较短的波长敏感的视蛋白的昆虫之间的序列比较预测，祖先节肢动物的视蛋白的赖氨酸残基负责紫外线的敏感性。这些结果有力地表明，祖先节肢动物至少有三色视觉与紫外线色素和两个可见色素。此后，在每一个泛甲壳动物和螯肢动物谱系中，视蛋白库通过基因丢失、基因复制和改变功能的氨基酸取代来重建，从而导致色觉的进化。
Among terrestrial animals, only vertebrates and arthropods possess wavelength-discrimination ability, so-called "color vision". For color vision to exist, multiple opsins which encode visual pigments sensitive to different wavelengths of light are required. While the molecular evolution of opsins in vertebrates has been well investigated, that in arthropods remains to be elucidated. This is mainly due to poor information about the opsin genes of non-insect arthropods. To obtain an overview of the evolution of color vision in Arthropoda, we isolated three kinds of opsins, Rh1, Rh2, and Rh3, from two jumping spider species, Hasarius adansoni and Plexippus paykulli. These spiders belong to Chelicerata, one of the most distant groups from Hexapoda (insects), and have color vision as do insects. Phylogenetic analyses of jumping spider opsins revealed a birth and death process of color vision evolution in the arthropod lineage. Phylogenetic positions of jumping spider opsins revealed that at least three opsins had already existed before the Chelicerata-Pancrustacea split. In addition, sequence comparison between jumping spider Rh3 and the shorter wavelength-sensitive opsins of insects predicted that an opsin of the ancestral arthropod had the lysine residue responsible for UV sensitivity. These results strongly suggest that the ancestral arthropod had at least trichromatic vision with a UV pigment and two visible pigments. Thereafter, in each pancrustacean and chelicerate lineage, the opsin repertoire was reconstructed by gene losses, gene duplications, and function-altering amino acid substitutions, leading to evolution of color vision.