Sciarids, also called “fungus gnats” are small, almost entirely dark-coloured insects. Sciarid larvae feed on different substrates and can infest agricultural crops and mushroom nurseries, causing economic losses. Of the 2174 Diptera mitogenome sequences currently available in GenBank, only eight are from the Sciaridae family, none of which are complete circular molecules. Here we describe the mitogenome sequences of three sciarid species: Phytosciara flavipes, Trichosia splendens and Bradysia hygida and provide novel insights on the control region of sciarid mitogenomes. The assembled mitogenomes range from 16,062 bp in P. flavipes to 17,095 bp in B. hygida. All 13 protein coding genes, 22 tRNAs and 2 rRNAs characteristic of insect mitogenomes were identified, but the sequence of the control region could not be determined. Experimental results suggest that the B. hygida control region is about 21 kb long resulting in a 37 kb long mitogenome which constitutes the largest insect mitochondrial genome described so far. Phylogenetic analysis using all Bibionomorpha mitogenome sequences available in GenBank strongly supports the Sciaridae monophyly and led to the identification of species and subfamily specific gene rearrangements. Our study extends the knowledge of this large and diverse insect family that includes agricultural pest species.

中文翻译：

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Bradysia hygida、Phytosciara flavipes 和 Trichosia splendens (Diptera: Sciaridae) 线粒体基因组的表征以及对 sciarid mitogenomes 控制区的新见解

Sciarids，也称为“fungus gnats”，是一种几乎完全是深色的小型昆虫。Sciarid 幼虫以不同的基质为食，可侵染农作物和蘑菇苗圃，造成经济损失。目前在 GenBank 中可用的 2174 个双翅目有丝分裂基因组序列中，只有 8 个来自 Sciaridae 家族，它们都不是完整的环状分子。在这里，我们描述了三种 sciarid 物种的有丝分裂基因组序列：Phytosciara flavipes、Trichosia splendens和Bradysia hygida，并提供了关于 sciarid 有丝分裂基因组控制区域的新见解。组装的有丝分裂基因组范围从P. flavipes中的 16,062 bp 到B. hygida中的 17,095 bp. 所有13个蛋白质编码基因、22个tRNAs和2个rRNAs都是昆虫有丝分裂基因组的特征，但无法确定控制区的序列。实验结果表明，B. hygida控制区域长约 21 kb，导致 37 kb 长的有丝分裂基因组构成了迄今为止描述的最大的昆虫线粒体基因组。使用 GenBank 中可用的所有 Bibion​​omorpha mitogenome 序列的系统发育分析强烈支持 Sciaridae 单系并导致物种和亚科特异性基因重排的鉴定。我们的研究扩展了包括农业害虫物种在内的这一庞大而多样的昆虫家族的知识。