The diadem (Hypolimnas misippus) is a widely distributed butterfly that is known for its female-limited mimicry of three forms of the African queen (Danaus chrysippus). All H. misippus males are non-mimetic and have black wings with prominent egg-like white spots, whereas females have orange wings and are polymorphic, mimicking one of three toxic butterfly subspecies. Writing in Molecular Biology and Evolution, Orteu and colleagues study the genetic architecture that underlies mimicry in H. misippus. They first developed a program that they named Wrath (‘WRapped Analysis of Tagged Haplotypes’), which enables them to detect structural variations in genomic data from linked-read sequencing. This represents an economic means of identifying candidate structural variants, which would otherwise require costly long-read sequencing data. Combining genome-wide association studies with Wrath-based analysis, the authors pinpointed a Mendelian locus that controls forewing mimicry in H. misippus. The dominant M allele at this locus is responsible for the mimetic phenotype of black-and-white forewing tips in two female forms, and this allele contains several transposable elements that are absent in the recessive m allele. Comparing sequences across Hypolimnas species, the authors determined that the M allele of H. misippus is unique in this genus in containing transposable elements and is derived from the ancestral m allele. Orteu and colleagues propose that the m allele became fixed at some point in the evolutionary history of Hypolimnas species, and that the emergence of the M allele in H. misippus represents reversion to an ancestral phenotype that is then used for mimicry. Such atavisms are typically maladaptive, which makes this an unusual case in which reversion to an ancestral state has adaptive benefits.

Original reference: Mol. Biol. Evol. 41, msae041 (2024)

王冠蝴蝶 ( Hypolimnas misippus ) 是一种分布广泛的蝴蝶，以其雌性有限模仿非洲女王 ( Danaus chrysippus ) 的三种形态而闻名。所有的H. misippus雄性都是非模仿性的，有黑色的翅膀，上面有明显的鸡蛋状白色斑点，而雌性有橙色的翅膀，并且是多态性的，模仿三种有毒蝴蝶亚种之一。 Orteu 及其同事在《分子生物学与进化》杂志上撰文，研究了米西波斯 拟态背后的遗传结构。他们首先开发了一个名为 Wrath 的程序（“标记单倍型的 WRapped 分析”），该程序使他们能够通过链接读取测序检测基因组数据中的结构变异。这代表了一种识别候选结构变异的经济方法，否则需要昂贵的长读长测序数据。作者将全基因组关联研究与基于 Wrath 的分析相结合，确定了控制H. misippus前翅拟态的孟德尔基因座。该基因座的显性M等位基因负责两种雌性形式中黑白前翅尖的模仿表型，并且该等位基因包含隐性m等位基因中不存在的几个转座元件。通过比较Hypolimnas物种的序列，作者确定H. misippus的M等位基因在该属中是独一无二的，因为含有转座元件，并且源自祖先m等位基因。 Orteu 及其同事提出，m等位基因在Hypolimnas物种进化史上的某个时刻被固定，而M等位基因在H. misippus中的出现代表着向祖先表型的回归，然后用于拟态。这种返祖现象通常是适应不良的，这使得这是一个不寻常的案例，其中回归祖先状态具有适应性益处。

原始参考文献： Mol.生物。进化。 41、msae041（2024）