PDF(Pubmed)
Abstract：
The threespine stickleback (Gasterosteus aculeatus) is an important model for studying the evolution of nuptial coloration, but histological analyses of color are largely lacking. Previous analyses of one nuptial coloration trait, orange-red coloration along the body, have indicated carotenoids are the main pigment producing this color. In addition, recent gene expression studies found variation in the correlates of throat coloration between the sexes and between populations, raising the possibility of variation in the mechanisms underlying superficially similar coloration. We used transmission electron microscopy (TEM) to investigate the histological correlates of color in the throat dermal tissue of threespine stickleback from Western North America, within and between sexes, populations, and ecotypes. Ultrastructural analysis revealed carotenoid-containing erythrophores to be the main chromatophore component associated with orange-red coloration in both males and females across populations. In individuals where some darkening of the throat tissue was present, with no obvious orange-red coloration, erythrophores were not detected. Melanophore presence was more population-specific in expression, including being the only chromatophore component detected in a population of darker fish. We found no dermal chromatophore units within colorless throat tissue. This work confirms the importance of carotenoids and the erythrophore in producing orange-red coloration across sexes, as well as melanin within the melanophore in producing darkened coloration, but does not reveal broad histological differences among populations with similar coloration.
摘要：
三松树刺背鱼（Gasterosteusaculeatus）是研究新婚颜色演化的重要模型，但是对颜色的组织学分析在很大程度上是缺乏的。以前对一种婚姻色彩特征的分析，身体上的橙红色，已经表明类胡萝卜素是产生这种颜色的主要色素。此外,最近的基因表达研究发现性别之间和人群之间喉咙颜色的相关性存在差异，提高了表面相似着色机制变化的可能性。我们使用透射电子显微镜（TEM）研究了来自北美西部的三叶松stickleback的喉咙真皮组织中颜色的组织学相关性，在性别内部和性别之间，人口,和生态型。超微结构分析显示，含类胡萝卜素的红色素是种群中男性和女性中与橙红色相关的主要色团成分。在喉咙组织变黑的个体中，没有明显的橙红色，未检测到红细胞。黑色素团的存在在表达上更具群体特异性，包括在较黑的鱼类种群中检测到的唯一的色团成分。我们在无色的咽喉组织中没有发现真皮色团单位。这项工作证实了类胡萝卜素和红斑在跨性别产生橙红色着色中的重要性，以及黑色素中的黑色素产生变暗的颜色，但没有揭示具有相似颜色的人群之间的广泛组织学差异。
