The evolutionary dynamics of large gene families can offer important insights into the functions of their individual members. While the ecdysteroid kinase-like (EcKL) gene family has previously been linked to the metabolism of both steroid moulting hormones and xenobiotic toxins, the functions of nearly all EcKL genes are unknown and there is little information on their evolution across all insects. Here, we perform comprehensive phylogenetic analyses on a manually annotated set of EcKL genes from 140 insect genomes, revealing the gene family is comprised of at least 13 subfamilies that differ in retention and stability. Our results show the only two genes known to encode ecdysteroid kinases belong to different subfamilies and therefore ecdysteroid metabolism functions must be spread throughout the EcKL family. We provide comparative phylogenomic evidence that EcKLs are involved in detoxification across insects, with positive associations between family size and dietary chemical complexity, and we also find similar evidence for the cytochrome P450 and glutathione S-transferase gene families. Unexpectedly, we find that the size of the clade containing a known ecdysteroid kinase is positively associated with host plant taxonomic diversity in Lepidoptera, possibly suggesting multiple functional shifts between hormone and xenobiotic metabolism. Our evolutionary analyses provide hypotheses of function and a robust framework for future experimental studies of the EcKL gene family. They also open promising new avenues for exploring the genomic basis of dietary adaptation in insects, including the classically studied co-evolution of butterflies with their host plants.

中文翻译：

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昆虫蜕皮激素激酶样 (EcKL) 基因家族的系统基因组学强调了类固醇激素代谢和解毒中的作用

大基因家族的进化动态可以为其个体成员的功能提供重要的见解。虽然蜕皮类固醇激酶 (EcKL) 基因家族先前已被认为与类固醇蜕皮激素和外源毒素的代谢有关，但几乎所有 EcKL 基因的功能都是未知的，而且关于它们在所有昆虫中进化的信息也很少。在这里，我们对来自 140 个昆虫基因组的一组手动注释的 EcKL 基因进行了全面的系统发育分析，揭示了该基因家族由至少 13 个在保留和稳定性方面不同的亚家族组成。我们的结果表明，已知编码蜕皮类固醇激酶的唯一两个基因属于不同的亚家族，因此蜕皮类固醇代谢功能必须遍布整个 EcKL 家族。我们提供了比较系统发育学证据，表明 EcKL 参与昆虫的解毒，家族规模和膳食化学复杂性之间呈正相关，并且我们还发现了细胞色素 P450 和谷胱甘肽 S-转移酶基因家族的类似证据。出乎意料的是，我们发现含有已知蜕皮类固醇激酶的进化枝的大小与鳞翅目宿主植物分类多样性呈正相关，这可能表明激素和外源代谢之间存在多种功能转变。我们的进化分析为 EcKL 基因家族的未来实验研究提供了功能假设和稳健的框架。他们还为探索昆虫饮食适应的基因组基础开辟了有希望的新途径，包括经典研究的蝴蝶与其寄主植物的共同进化。