In Heliconius butterflies, wing pattern diversity is controlled by a few genes of large effect that regulate colour pattern switches between morphs and species across a large mimetic radiation. One of these genes, cortex, has been repeatedly associated with colour pattern evolution. Here we carried out CRISPR knock-outs in multiple Heliconius species and show that cortex is a major determinant of scale cell identity. Chromatin accessibility profiling and introgression scans identified cis-regulatory regions associated with discrete phenotypic switches. CRISPR perturbation of these regions in black hindwing genotypes recreated a yellow bar, revealing their spatially limited activity. In the H. melpomene/timareta lineage, the candidate CRE from yellow-barred phenotype morphs is interrupted by a transposable element, suggesting that cis-regulatory structural variation underlies these mimetic adaptations. Our work shows that cortex functionally controls scale colour fate and that its cis-regulatory regions control a phenotypic switch in a modular and pattern-specific fashion.

中文翻译：

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皮质Cortex顺式调节开关可在Heliconius中建立标度颜色标识和图案多样性

在Heliconius蝴蝶中，机翼模式的多样性受少数几个效果显着的基因控制，这些基因可在较大的模拟辐射中调节形态和物种之间的颜色模式转换。这些基因之一，皮层，已与颜色模式演变反复相关。在这里，我们在多个Heliconius物种中进行了CRISPR敲除，表明皮层是规模细胞身份的主要决定因素。染色质可及性分析和基因渗入扫描确定了与离散表型开关相关的顺式调控区域。黑色后代基因型中这些区域的CRISPR扰动重现了黄色条状图，显示了它们在空间上有限的活性。在H. melpomene / timareta血统中，来自黄禁止表型形态的候选CRE被可转座因子打断，提示顺式调控结构变异是这些模拟适应的基础。我们的工作表明，皮质在功能上控制鳞片的颜色命运，其顺式调节区域以模块化和特定于模式的方式控制表型转换。