Department of Ecology and Evolutionary Biology, Tulane University, New Orleans, LA, USA.
Macaulay Library, Cornell Laboratory of Ornithology, Ithaca, NY, USA.
Proc Biol Sci. 2020 Sep 30;287(1935):20201687. doi: 10.1098/rspb.2020.1687. Epub 2020 Sep 16.
Carotenoid pigments produce most red, orange and yellow colours in vertebrates. This coloration can serve as an honest signal of quality that mediates social and mating interactions, but our understanding of the underlying mechanisms that control carotenoid signal production, including how different physiological pathways interact to shape and maintain these signals, remains incomplete. We investigated the role of testosterone in mediating gene expression associated with a red plumage sexual signal in red-backed fairywrens (). In this species, males within a single population can flexibly produce either red/black nuptial plumage or female-like brown plumage. Combining correlational analyses with a field-based testosterone implant experiment and quantitative polymerase chain reaction, we show that testosterone mediates expression of carotenoid-based plumage in part by regulating expression of , a ketolase gene associated with ketocarotenoid metabolism and pigmentation in birds. This is, to our knowledge, the first time that hormonal regulation of a specific genetic locus has been linked to carotenoid production in a natural context, revealing how endocrine mechanisms produce sexual signals that shape reproductive success.
类胡萝卜素色素使脊椎动物产生大多数红色、橙色和黄色。这种颜色可以作为一种诚实的质量信号，调节社交和交配互动，但我们对控制类胡萝卜素信号产生的潜在机制的理解还不完整，包括不同的生理途径如何相互作用来塑造和维持这些信号。我们研究了睾酮在介导与红背仙鹟（）红色羽毛性信号相关的基因表达中的作用。在这个物种中，同一群体中的雄性可以灵活地产生红色/黑色婚羽或类似于雌性的棕色羽毛。我们将相关性分析与基于野外的睾酮植入实验和定量聚合酶链反应相结合，表明睾酮通过调节与鸟类酮类胡萝卜素代谢和色素沉着有关的酮基酶基因的表达来介导基于类胡萝卜素的羽毛表达。据我们所知，这是荷尔蒙调节特定基因座与自然环境中类胡萝卜素产生首次相关联，揭示了内分泌机制如何产生影响繁殖成功的性信号。
