Batesian mimicry protects animals from predators when mimics resemble distasteful models. The female-limited Batesian mimicry in Papilio butterflies is controlled by a supergene locus switching mimetic and nonmimetic forms. In Papilio polytes, recent studies revealed that a highly diversified region (HDR) containing doublesex (dsx-HDR) constitutes the supergene with dimorphic alleles and is likely maintained by a chromosomal inversion. In the closely related Papilio memnon, which exhibits a similar mimicry polymorphism, we performed whole-genome sequence analyses in 11 butterflies, which revealed a nearly identical dsx-HDR containing three genes (dsx, Nach-like, and UXT) with dimorphic sequences strictly associated with the mimetic/nonmimetic phenotypes. In addition, expression of these genes, except that of Nach-like in female hind wings, showed differences correlated with phenotype. The dimorphic dsx-HDR in P. memnon is maintained without a chromosomal inversion, suggesting that a separate mechanism causes and maintains allelic divergence in these genes. More abundant accumulation of transposable elements and repetitive sequences in the dsx-HDR than in other genomic regions may contribute to the suppression of chromosomal recombination. Gene trees for Dsx, Nach-like, and UXT indicated that mimetic alleles evolved independently in the two Papilio species. These results suggest that the genomic region involving the above three genes has repeatedly diverged so that two allelic sequences of this region function as developmental switches for mimicry polymorphism in the two Papilio species. The supergene structures revealed here suggest that independent evolutionary processes with different genetic mechanisms have led to parallel evolution of similar female-limited polymorphisms underlying Batesian mimicry in Papilio butterflies.

中文翻译：

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两种凤蝶（P. polytes 和 P. memnon）中贝氏拟态超基因的平行进化。

当模仿者与令人厌恶的模型相似时，贝茨拟态可以保护动物免受捕食者的伤害。凤蝶中雌性有限的贝氏拟态是由一个表基因位点切换拟态和非拟态形式控制的。在凤蝶中，最近的研究表明，包含双性（dsx -HDR ）的高度多样化区域（HDR）构成了具有二态性等位基因的超基因，并且可能是通过染色体倒位维持的。在表现出类似拟态多态性的密切相关的凤蝶 memnon中，我们对 11 只蝴蝶进行了全基因组序列分析，结果显示几乎相同的dsx -HDR 包含三个严格具有二态性序列的基因（dsx、Nach-like和UXT）与模仿/非模仿表型相关。此外，除了雌性后翅中的Nach-like基因外，这些基因的表达显示出与表型相关的差异。P. memnon中的二态性dsx -HDR在没有染色体倒位的情况下得以维持，这表明单独的机制导致并维持了这些基因中的等位基因分歧。dsx -HDR中转座元件和重复序列的积累比其他基因组区域更丰富，可能有助于抑制染色体重组。Dsx、Nach-like 和 UXT 的基因树表明，模拟等位基因在两个凤蝶物种中独立进化。这些结果表明，涉及上述三个基因的基因组区域反复发生分歧，因此该区域的两个等位基因序列在两个凤蝶物种中充当拟态多态性的发育开关。这里揭示的表基因结构表明，具有不同遗传机制的独立进化过程导致了凤蝶贝氏拟态基础上类似雌性有限多态性的平行进化。