Parallelism of amino acid changes at the RH1 affecting spectral sensitivity among deep-water cichlids from Lakes Tanganyika and Malawi
Parallelism of amino acid changes at the RH1 affecting spectral sensitivity among deep-water cichlids from Lakes Tanganyika and Malawi
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DOI：
10.1073/pnas.0405302102
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发表时间：
2005-04-12
影响因子：
11.1
通讯作者：
Okada, N
中科院分区：
文献类型：
--
作者：
Sugawara, T;Terai, Y;Okada, N
在生物体的进化过程中，已知许多不同谱系中出现相似特征的例子。然而，在极少数情况下，潜在的遗传机制得到了阐明。在这里，我们提供了一个进化平行性的明显例子，涉及相同遗传途径的变化，在东非慈鲷鱼的适应性辐射过程中提供了 RH1 色素对深水栖息地的功能适应。我们确定了 233 种慈鲷个体的 RH1 序列。用来自 28 个序列的 11-顺式视黄醛重建丽鱼科鱼 RH1 色素表明，通过两种特定的氨基酸替换调整，九种色素的吸收光谱向蓝色移动。这些蓝移 RH1 颜料可能是为了适应深水光环境而进化的。系统发育证据表明，其中一种替代物 A292S 已经独立进化了多次，引发了类似的功能变化。相同氨基酸位置上相同突变的平行进化表明，慈鲷多样化中出现相似性状的遗传变化数量可能比之前预期的要少。
Many examples of the appearance of similar traits in different lineages are known during the evolution of organisms. However, the underlying genetic mechanisms have been elucidated in very few cases. Here, we provide a clear example of evolutionary parallelism, involving changes in the same genetic pathway, providing functional adaptation of RH1 pigments to deep-water habitats during the adaptive radiation of East African cichlid fishes. We determined the RH1 sequences from 233 individual cichlids. The reconstruction of cichlid RH1 pigments with 11-cis-retinal from 28 sequences showed that the absorption spectra of the pigments of nine species were shifted toward blue, tuned by two particular amino acid replacements. These blue-shifted RH1 pigments might have evolved as adaptations to the deep-water photic environment. Phylogenetic evidence indicates that one of the replacements, A292S, has evolved several times independently, inducing similar functional change. The parallel evolution of the same mutation at the same amino acid position suggests that the number of genetic changes underlying the appearance of similar traits in cichlid diversification may be fewer than previously expected.