Positive selection of a duplicated UV-sensitive visual pigment coincides with wing pigment evolution in Heliconius butterflies
Positive selection of a duplicated UV-sensitive visual pigment coincides with wing pigment evolution in Heliconius butterflies
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DOI：
10.1073/pnas.0910085107
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发表时间：
2010-02-23
影响因子：
11.1
通讯作者：
Chiao, Chuan-Chin
中科院分区：
文献类型：
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作者：
Briscoe, Adriana D.;Bybee, Seth M.;Chiao, Chuan-Chin
蝴蝶Heliconius erato可以看到从紫外线到红色光谱的一部分，色觉范围为440至640 nm。已知其眼睛含有三种视色素，视紫红质，由11-顺式-3-羟基视网膜发色团与长波长（LWRh）、蓝色（BRh）和UV（UVRh 1）视蛋白一起产生。我们现在发现H。erato有第二个UV视蛋白mRNA（UVRh 2）-以前没有描述的复制该基因之间的鳞翅目。为了研究其进化起源，我们筛选了Heliconiinae亚科14种蝴蝶的眼睛cDNA，发现这两个副本只在Heliconius中。系统发育为基础的测试的选择表明积极选择UVRh 2重复后，和一些积极选择的网站对应于脊椎动物的视觉色素光谱调谐残基。用差示显微分光光度法测定了H.人眼λ（max）= 355 nm和398 nm。沿着额外的UV视蛋白，Heliconius还进化出了在近亲中没有发现的基于3-羟基-DL-犬尿氨酸（3-OHK）的黄色翅膀色素。蝴蝶如何感知翅膀颜色变化的视觉模型表明，这导致了Heliconius翅膀上可区分的黄色数量的扩大。紫外线敏感视觉色素的功能多样化可能有助于解释为什么与缺乏紫外线视蛋白复制品的近亲的黄色色素相比，Heliconius的黄色翅膀色素在紫外线范围内如此丰富多彩。
The butterfly Heliconius erato can see from the UV to the red part of the light spectrum with color vision proven from 440 to 640 nm. Its eye is known to contain three visual pigments, rhodopsins, produced by an 11-cis-3-hydroxyretinal chromophore together with long wavelength (LWRh), blue (BRh) and UV (UVRh1) opsins. We now find that H. erato has a second UV opsin mRNA (UVRh2)-a previously undescribed duplication of this gene among Lepidoptera. To investigate its evolutionary origin, we screened eye cDNAs from 14 butterfly species in the subfamily Heliconiinae and found both copies only among Heliconius. Phylogeny-based tests of selection indicate positive selection of UVRh2 following duplication, and some of the positively selected sites correspond to vertebrate visual pigment spectral tuning residues. Epi-microspectrophotometry reveals two UV-absorbing rhodopsins in the H. erato eye with lambda(max) = 355 nm and 398 nm. Along with the additional UV opsin, Heliconius have also evolved 3-hydroxy-DL-kynurenine (3-OHK)-based yellow wing pigments not found in close relatives. Visual models of how butterflies perceive wing color variation indicate this has resulted in an expansion of the number of distinguishable yellow colors on Heliconius wings. Functional diversification of the UV-sensitive visual pigments may help explain why the yellow wing pigments of Heliconius are so colorful in the UV range compared to the yellow pigments of close relatives lacking the UV opsin duplicate.