Natural selection of the rhodopsin gene during the adaptive radiation of East African Great Lakes cichlid fishes.
Natural selection of the rhodopsin gene during the adaptive radiation of East African Great Lakes cichlid fishes.
复制标题
DOI：
10.1093/oxfordjournals.molbev.a004004
复制
发表时间：
2002-10
影响因子：
10.7
通讯作者：
T. Sugawara;Y. Terai;N. Okada
中科院分区：
文献类型：
--
作者：
T. Sugawara;Y. Terai;N. Okada
东非大裂谷的五大湖、维多利亚湖、马拉维湖和坦噶尼喀湖分别拥有大约200种、400种和170种特有的慈鲷鱼（Fryer and Iles 1972，pp. 6-590; Greenwood 1991）。这些鱼类吸引了进化生物学家，因为这些鱼类已经适应了湖泊中的各种生态位（Fryer和Iles 1972; Greenwood 1984），它们是脊椎动物中爆炸性适应辐射的壮观例子。因此，尽管它们的进化时间很短，但它们在生态和形态上都极为多样（Meyer等人，1990年; Sturmbauer和Meyer，1992年;约翰逊等人，1996年; Takahashi等人，2001年）。这些鱼的视觉系统特别令人感兴趣，因为它们对于摄食（Fryer和Iles 1972）以及配偶选择（Seehausen，货车Alphen和Witte 1997; Seehausen和货车Alphen 1998）非常重要，并且慈鲷科鱼类适应了随深度和时间变化的不同光照条件（Fryer和Iles 1972; Coulter 1991）。此外，共存的慈鲷物种之间的视觉能力的差异可能会减少对资源的竞争（货车der梅尔和Bowmaker 1995）。因此，我们有理由假设，在非洲五大湖的慈鲷鱼适应性辐射过程中，对视力至关重要的基因必须适应性地进化。我们试图通过关注慈鲷视蛋白基因来鉴定这些基因。视觉色素由与蛋白质视蛋白结合的吸光发色团（通常为11-顺式视网膜）组成（Wald 1968）。发色团的吸收光谱可以通过视蛋白内的氨基酸取代来改变，并且关键取代位点位于靠近视网膜结合口袋的七个跨膜α-螺旋中（Yokoyama R.和Yokoyama S. 1990; Yokoyama S.和Yokoyama R. 1996; Kochendoerfer等人1999）。慈鲷有六种已知的视蛋白基因，其产物对不同波长的可见-紫外光敏感，即SWS-1（紫外光）、SWS-2A和SWS-2B（短波长）、RH 2（中波长）、LWS（长波长）（Carleton，Harosi，and Kocher 2000; Carleton and Kocher 2001）和视紫红质（GenBank登录号AF 315354）。视紫红质定位于视杆细胞，使黑色和白色图像在昏暗的光线下被看到
The Great Lakes of the East African Rift Valley, Lakes Victoria, Malawi, and Tanganyika, harbor approximately 200, 400, and 170 endemic species of cichlid fishes, respectively (Fryer and Iles 1972, pp. 6–590; Greenwood 1991). These fishes have fascinated evolutionary biologists as spectacular examples of explosive adaptive radiation among living vertebrates because the fishes have adapted to a variety of niches in the lakes (Fryer and Iles 1972; Greenwood 1984). Accordingly, they are extremely diverse, both ecologically and morphologically, despite having evolved over a very short period (Meyer et al. 1990; Sturmbauer and Meyer 1992; Johnson et al. 1996; Takahashi et al. 2001). The visual systems of these fishes are of particular interest because they are important for feeding (Fryer and Iles 1972) as well as for mate choice (Seehausen, van Alphen, and Witte 1997; Seehausen and van Alphen 1998), and cichlids have adapted to different photic conditions that vary with depth and time of day (Fryer and Iles 1972; Coulter 1991). Furthermore, differences in visual capabilities among coexisting cichlid species may reduce the competition for resources (van der Meer and Bowmaker 1995). Therefore, it is reasonable to postulate that genes that are essential for visual acuity must have evolved adaptively during adaptive radiation of the cichlids in these African Great Lakes. We attempted to identify such genes by focusing on cichlid opsin genes. Visual pigments are composed of a light-absorbing chromophore, typically 11-cis-retinal, that is bound to the protein opsin (Wald 1968). The absorption spectrum of the chromophore can be altered by amino acid substitutions within opsin, and key substitution sites are located in the seven transmembrane a-helices that lie close to the retinal-binding pocket (Yokoyama R. and Yokoyama S. 1990; Yokoyama S. and Yokoyama R. 1996; Kochendoerfer et al. 1999). Cichlids have six known opsin genes whose products are sensitive to different wavelengths of visible-ultraviolet light, namely SWS-1 (ultraviolet), SWS-2A and SWS-2B (short wavelength), RH2 (midwavelength), LWS (long wavelength) (Carleton, Harosi, and Kocher 2000; Carleton and Kocher 2001), and rhodopsin (GenBank accession number AF315354). Rhodopsin is localized to rod cells that enable black and white images to be seen in dim light