Correlation between Nuptial Colors and Visual Sensitivities Tuned by Opsins Leads to Species Richness in Sympatric Lake Victoria Cichlid Fishes
Correlation between Nuptial Colors and Visual Sensitivities Tuned by Opsins Leads to Species Richness in Sympatric Lake Victoria Cichlid Fishes
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DOI：
10.1093/molbev/mss139
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发表时间：
2012-11-01
影响因子：
10.7
通讯作者：
Okada, Norihiro
中科院分区：
文献类型：
--
作者：
Miyagi, Ryutaro;Terai, Yohey;Okada, Norihiro
生殖隔离，防止种间杂交密切相关的共存物种保持同域物种多样性。生殖隔离之一是基于颜色信号（通过色觉感知的繁殖颜色）的择偶。这在几种动物类群中是众所周知的，但对其遗传和分子机制知之甚少。维多利亚湖慈鲷鱼被认为是同域物种多样性的一个例子。通过对长波长敏感（LWS）视蛋白基因和雄性交配色的分析，提出了在不同光照环境下的岩石海岸物种通过颜色信号的感觉驱动形成物种的观点。然而，发生在同一生境的同域物种的多样性如何保持的遗传和分子机制仍然未知。为了解决这个问题，我们确定了八个视蛋白的核苷酸序列的六个同域物种收集从一个砂泥海岸-一个理想的模型系统，研究同域物种。在8个视蛋白中，LWS和RH 1等位基因是多样化的，并且一个特定的等位基因在每个物种中是显性的或固定的，我们认为这是由于自然选择。重组视色素的吸收测定结果表明，它们的LWS等位基因的功能也是多样化的。为了分析婚色与LWS色素吸收之间的关系，我们对婚色进行了系统的评价和定义。我们发现，着色是物种特异性的色调和显着区分的指数值的色调（主波长：λ（d））。男性婚礼颜色的λ（d）值与所有物种的LWS色素的吸收相关，这表明生殖隔离，通过配偶选择使用颜色信号可能会阻止同域种间杂交，从而保持物种多样性在同域物种在维多利亚湖。
Reproductive isolation that prevents interspecific hybridization between closely related coexisting species maintains sympatric species diversity. One of the reproductive isolations is mate choice based on color signals (breeding color perceived by color vision). This is well known in several animal taxa, yet little is known about its genetic and molecular mechanism. Lake Victoria cichlid fishes are thought to be an example of sympatric species diversity. In the species inhabiting different light environments in rocky shore, speciation by sensory drive through color signals has been proposed by analyses of the long wavelength-sensitive (LWS) opsin gene and the male nuptial coloration. However, the genetic and molecular mechanism of how diversity of sympatric species occurring in the same habitat is maintained remains unknown. To address this issue, we determined nucleotide sequences of eight opsins of six sympatric species collected from a sandy-muddy shore-an ideal model system for studying sympatric species. Among eight opsins, the LWS and RH1 alleles were diversified and one particular allele is dominant or fixed in each species, and we propose that this is due to natural selection. The functions of their LWS alleles were also diversified as shown by absorption measurements of reconstituted visual pigments. To analyze the relationship between nuptial coloration and the absorption of LWS pigments, we systematically evaluated and defined nuptial coloration. We showed that the coloration was species specific with respect to hue and significantly differentiated by the index values of hue (dominant wavelength: lambda(d)). The lambda(d) value of the male nuptial coloration correlated with the absorption of LWS pigments from all the species, suggesting that reproductive isolation through mate choice using color signals may prevent sympatric interspecific hybridization, thereby maintaining the species diversity in sympatric species in Lake Victoria.