Data from: Revealing the biochemical and genetic basis of color variation in a polymorphic lizard

Determining the mechanistic and genetic basis of animal coloration is essential to understand the costs and constraints on colour production, and the evolution and maintenance of phenotypic variation. However, genes underlying structural colour and widespread pigment classes apart from melanin remain largely uncharacterised, in part due to restricted taxonomic focus. We combined liquid chromatography-mass spectrometry and RNA-seq gene expression analyses to characterise the pigments and genes associated with skin colour in the polymorphic lizard, Ctenophorus decresii. Throat coloration in male C. decresii may be a combination of orange, yellow, grey or ultra-violet blue. We confirmed the presence of two biochemically different pigment classes, pteridines (self-synthesised) and carotenoids (acquired through the diet), in all skin colours. Orange skin had the highest levels of pteridine pigments while yellow skin tended to have higher levels of carotenoids, of which the vitamin A precursors β-carotene and β-cryptoxanthin have not been previously confirmed in reptiles. These results were confirmed by gene expression analyses, which detected 489 genes differentially expressed between the skin colours, including genes associated with pteridine production, provitamin A carotenoid metabolism, iridophore-specific synthesis, melanin synthesis and steroid hormone pathways. For the majority of these 489 genes, however, our study reveals a new association with colour production in vertebrates. These data represent a significant contribution to understanding the genetic basis of colour variation in vertebrates and a rich resource for further studies.

解析动物体色的机制与遗传基础，对于理解体色产生的代价与限制，以及表型变异的演化与维持至关重要。然而，除黑色素外，结构性体色相关的基因以及多数常见色素类别的遗传基础仍未得到充分解析，这在一定程度上源于研究类群的聚焦范围受限。本研究结合液相色谱-质谱联用（liquid chromatography-mass spectrometry）与RNA测序（RNA-seq）基因表达分析，对多态性蜥蜴项鼻龙（Ctenophorus decresii）皮肤体色相关的色素与基因进行了表征。雄性项鼻龙的喉部体色可呈现橙色、黄色、灰色或紫外蓝色的组合。我们确认所有皮肤体色样本中均存在两类生化特性迥异的色素：蝶啶（pteridines，自身合成）与类胡萝卜素（carotenoids，通过饮食获取；橙色皮肤中的蝶啶类色素含量最高，而黄色皮肤的类胡萝卜素含量通常更高，其中作为维生素A前体的β-胡萝卜素与β-隐黄质此前从未在爬行动物中得到证实。上述结果得到了基因表达分析的验证：该分析检测到489个在不同皮肤体色间存在差异表达的基因，其中包括与蝶啶合成、维生素A原类胡萝卜素代谢、虹色素细胞（iridophore）特异性合成、黑色素合成以及类固醇激素通路相关的基因。然而，在这489个基因中，绝大多数与脊椎动物体色产生相关的关联均为本研究首次揭示。本研究数据为解析脊椎动物体色变异的遗传基础提供了重要支撑，同时也为后续相关研究提供了宝贵的资源。