The eyes have it: regulatory and structural changes both underlie cichlid visual pigment diversity.
The eyes have it: regulatory and structural changes both underlie cichlid visual pigment diversity.
复制标题
DOI：
10.1371/journal.pbio.1000266
复制
发表时间：
2009-12
期刊：
影响因子：
9.8
通讯作者：
Carleton KL
中科院分区：
文献类型：
--
作者：
Hofmann CM;O'Quin KE;Marshall NJ;Cronin TW;Seehausen O;Carleton KL
基因差异表达和编码序列进化在丽鱼感觉系统适应性多样化中起着互补的作用。进化生物学的一个主要目标是揭示功能多样化和适应性的分子遗传机制。我们研究了如何在基因调控和编码序列的变化有助于感官多样化的两个复制辐射的慈鲷鱼。在马拉维湖清澈的沃茨中，不同的视蛋白表达产生了不同的视觉系统，敏感度从紫外线延伸到光谱的红色区域。这些敏感性分为三个不同的集群，并与觅食习惯。在维多利亚湖浑浊的沃茨中，视觉灵敏度被限制在较长的波长，视蛋白表达与环境光相关。除了监管的变化，我们发现，编码最短和最长波长的视色素的视蛋白具有潜在的功能取代的数量增加。因此，我们提出了一个模型的感觉进化中，这两个分子遗传机制协同工作。基因表达的变化在整个集体视蛋白光谱范围内产生大的视色素敏感性变化，但编码序列的变化似乎在该范围的短波长和长波长端微调视色素敏感性，其中差异视蛋白表达不再能延长视色素敏感性。产生生物多样性的分子机制在很大程度上仍然难以捉摸。我们研究了其中两种机制，基因表达的变化和基因编码序列的变化，如何在快速形成的非洲慈鲷中产生了一套令人难以置信的多样化的视觉系统。我们发现在马拉维湖清澈的沃茨中栖息的慈鲷科鱼类的视锥细胞视蛋白基因表达存在很大差异。这些变化可能对视网膜敏感性产生强烈影响，并且似乎主要由不同的觅食需求驱动。然而，栖息在维多利亚湖浑浊沃茨中的慈鲷只表达了它们视蛋白基因的一个子集，基因表达的变化似乎主要由环境光的光谱驱动。当我们比较这些视蛋白基因的序列时，我们发现敏感范围的紫外线和红色边缘的基因变异更大。这些发现表明，基因表达和编码序列的变化可以是互补的，并协同工作，以产生感觉系统的变化。由于它们与生态因素的相关性，这些变化也可能是适应性的，并在这两个湖泊中产生了巨大的慈鲷多样性方面发挥了作用。
Differential gene expression and coding sequence evolution play complementary roles in the adaptive diversification of cichlid sensory systems. A major goal of evolutionary biology is to unravel the molecular genetic mechanisms that underlie functional diversification and adaptation. We investigated how changes in gene regulation and coding sequence contribute to sensory diversification in two replicate radiations of cichlid fishes. In the clear waters of Lake Malawi, differential opsin expression generates diverse visual systems, with sensitivities extending from the ultraviolet to the red regions of the spectrum. These sensitivities fall into three distinct clusters and are correlated with foraging habits. In the turbid waters of Lake Victoria, visual sensitivity is constrained to longer wavelengths, and opsin expression is correlated with ambient light. In addition to regulatory changes, we found that the opsins coding for the shortest- and longest-wavelength visual pigments have elevated numbers of potentially functional substitutions. Thus, we present a model of sensory evolution in which both molecular genetic mechanisms work in concert. Changes in gene expression generate large shifts in visual pigment sensitivity across the collective opsin spectral range, but changes in coding sequence appear to fine-tune visual pigment sensitivity at the short- and long-wavelength ends of this range, where differential opsin expression can no longer extend visual pigment sensitivity. The molecular mechanisms that generate biodiversity remain largely elusive. We examined how two of these mechanisms, changes in gene expression and changes in gene coding sequence, have generated an incredibly diverse set of visual systems in rapidly speciating African cichlids. We found large differences in cone opsin gene expression among cichlids inhabiting the clear waters of Lake Malawi. These changes are likely to have strong influences on retinal sensitivity and appear to be driven primarily by different foraging needs. Cichlids inhabiting the turbid waters of Lake Victoria, however, only expressed a subset of their opsin genes and variation in gene expression appears to by driven primarily by the spectrum of environmental light. When we compared the sequences of these opsin genes, we found greater variation in the genes at the ultraviolet and red edges of the sensitivity range. Taken together these findings suggest that changes in gene expression and coding sequence can be complementary and work in concert to generate changes in sensory systems. Because of their correlation with ecological factors, these changes are also likely to be adaptive and to have played a role in generating the tremendous diversity of cichlids in these two lakes.
登录
查看更多内容
影响因子：
1.8
作者：
FERNALD, RD;LIEBMAN, PA
通讯作者：
LIEBMAN, PA
影响因子：
2.1
作者：
Fuller, RC;Carleton, KL;Travis, J
通讯作者：
Travis, J
影响因子：
3.6
作者：
CODDINGTON, JA
通讯作者：
CODDINGTON, JA
影响因子：
3.9
作者：
Carleton, KL;Spady, TC;Cote, RH
通讯作者：
Cote, RH
影响因子：
10.7
作者：
Genner, Martin J.;Seehausen, Ole;Turner, Georg F.
通讯作者：
Turner, Georg F.