Adaptive phenotypes often arise by rewiring existing developmental networks. Co-option of transcription factors in novel contexts has facilitated the evolution of ecologically important adaptations. doublesex (dsx) governs fundamental sex differentiation during embryonic stages and has been co-opted to regulate diverse secondary sexual dimorphisms during pupal development of holometabolous insects. In Papilio polytes, dsx regulates female-limited mimetic polymorphism, resulting in mimetic and non-mimetic forms. To understand how a critical gene such as dsx regulates novel wing patterns while maintaining its basic function in sex differentiation, we traced its expression through metamorphosis in P. polytes using developmental transcriptome data. We found three key dsx expression peaks: (i) eggs in pre- and post-ovisposition stages; (ii) developing wing discs and body in final larval instar; and (iii) 3-day pupae. We identified potential dsx targets using co-expression and differential expression analysis, and found distinct, non-overlapping sets of genes—containing putative dsx-binding sites—in developing wings versus abdominal tissue and in mimetic versus non-mimetic individuals. This suggests that dsx regulates distinct downstream targets in different tissues and wing colour morphs and has perhaps acquired new, previously unknown targets, for regulating mimetic polymorphism. Additionally, we observed that the three female isoforms of dsx were differentially expressed across stages (from eggs to adults) and tissues and differed in their protein structure. This may promote differential protein–protein interactions for each isoform and facilitate sub-functionalization of dsx activity across its isoforms. Our findings suggest that dsx employs tissue-specific downstream effectors and partitions its functions across multiple isoforms to regulate primary and secondary sexual dimorphism through insect development.

适应性表型通常是通过重新连接现有的发育网络而产生的。在新的背景下，转录因子的共同选择促进了具有生态学意义的适应性进化。doublesex（dsx）在胚胎阶段控制着基本的性别分化，并且已被选为调控整体代谢昆虫p发育过程中多种次生性二态性的手段。在凤蝶polytes中，dsx调节女性有限的拟态多态性，产生拟态和非拟态形式。为了了解诸如dsx之类的关键基因如何在维持其性别分化基本功能的同时调节新型机翼模式，我们通过变态来追踪其表达。利用发育转录组数据研究多角体。我们发现了三个主要的dsx表达峰：（i）处于卵子放置前后的卵；（ii）在幼虫期末期发育翅片和尸体；（iii）3天的up。我们使用共表达和差异表达分析确定了潜在的dsx靶标，并在发育中的翅膀与腹部组织以及拟态与非拟态个体中发现了不同的，不重叠的基因集（包含推定的dsx结合位点）。这表明dsx调节不同组织和翅膀颜色形态中不同的下游靶标，并且可能已经获得了新的，以前未知的靶标，用于调节模拟多态性。此外，我们观察到dsx的三种雌性同工型在各个阶段（从卵到成虫）和组织之间差异表达，并且它们的蛋白质结构也不同。这可能会促进每种同工型之间蛋白质与蛋白质之间的差异相互作用，并促进其同工型中dsx活性的亚功能化。我们的发现表明，dsx使用组织特异性下游效应子，并将其功能划分为多种同工型，以通过昆虫发育来调节初级和次级性二态性。