Colour in a new light: a spectral perspective on the quantitative genetics of carotenoid colouration
Colour in a new light: a spectral perspective on the quantitative genetics of carotenoid colouration
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DOI：
10.1111/1365-2435.12297
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发表时间：
2015-01-01
影响因子：
5.2
通讯作者：
Sheldon, Ben C.
中科院分区：
文献类型：
--
作者：
Evans, Simon R.;Sheldon, Ben C.
1.基于类胡萝卜素的颜色是研究动物信号和性选择的模式特征，但尽管对可变表达的后果进行了广泛的研究，但其原因很少被量化。这个问题因基于类胡萝卜素的色块的复合性质而变得复杂，它结合了颜料和反射背景。最终，这种颜色的演变将由支配这些机制的不同表达的过程决定。我们提出了一种新的方法来评估颜色表达的数量遗传学，其中直接分析反射光谱，从而避免了数据丢失和总结颜色变量固有的主观性。此外，在光谱分析中可以区分组成机制的影响，因为它们具有不同的波长依赖性。利用一项为期6年的野生大山雀类胡萝卜素羽毛反射率研究的数据，我们使用了一种多平行动物模型的方法来估计可见光光谱中窄(2 Nm)波段的方差来源。中等遗传力估计仅限于光谱的紫蓝色区域，诊断羽毛中类胡萝卜素含量是可遗传的。出生环境的影响完全局限于紫蓝色，这再次表明它与羽毛中类胡萝卜素含量的变化有关。其他波长对年度和永久性环境变化敏感，但仅受到加性遗传差异的轻微影响。因此，背景反射率是对环境更敏感的组件。对反射光谱的分析直接提供了颜色表达动态的客观视角，这在依赖颜色总分时并不明显。在这种情况下，我们的结果表明，类胡萝卜素沉积可能是一个有效的选择目标，因此可以解释类胡萝卜素在种内信号传递中经常扮演的重要角色。
1. Carotenoid-based colours are model traits for research on animal signalling and sexual selection but, whereas the consequences of variable expression have been extensively studied, its causes are rarely quantified. This issue is complicated by the composite nature of carotenoid-based colour patches, which combine pigments and a reflective background. Ultimately, the evolution of such colours will be determined by the processes that govern variable expression of these mechanisms. We present a novel approach to assessing the quantitative genetics of colour expression, in which reflectance spectra are analysed directly, thereby avoiding the data loss and inherent subjectivity of summary colour variables. Further, the influence of the component mechanisms can be distinguished in spectral analyses due to their contrasting wavelength-dependencies. Using data from a 6-year study of carotenoid-based plumage reflectance in wild great tits (Parus major), we employ a multi-parallel animal modelling' approach to estimate sources of variance for narrow (2nm) wavebands across the visible spectrum. Moderate heritability estimates were limited to the violet-blue region of the spectrum, diagnostic of the carotenoid content of plumage being heritable. The natal environment effect was limited entirely to the violet-blue, again indicating that it relates to variation in carotenoid content of feathers. Other wavelengths were sensitive to annual and permanent environmental variation but only marginally influenced by additive genetic variation. Hence, background reflectance is the component that is more sensitive to the environment. Analysing reflectance spectra directly provided an objective perspective of the dynamics of colour expression that is not apparent when relying on summary colour scores. In this case, our results suggest that carotenoid deposition may be an effective target of selection and hence could explain the important role carotenoids frequently play in intraspecific signalling.