线粒体是广泛存在于真核生物中的一种重要的细胞器，是真核细胞的能量工厂。线粒体含有自身的DNA，其基因组中包含有核酸序列、氨基酸序列、基因重排和基因二级结构等各种类型的信息，为种群遗传结构、生物地理学和系统发育等研究提供了丰富的分子标记。
鳞翅目包括45-48个总科，是昆虫纲第二大类群。双孔类（Ditrysia）包含了98%的已知鳞翅目物种，被称为高等鳞翅类。以前对鳞翅目昆虫线粒体基因组研究主要集中在双孔类的7个总科。这些高等鳞翅目线粒体基因排列相同，与昆虫线粒体基因的原始排列相比有一个基因发生重排。云南蝠蛾（Thitarodes yunnanensis）和人支蝠蛾（Thitarodes renzhiensis）是名贵中药冬虫夏草的寄主昆虫，属于外孔类（Exoporia）蝙蝠蛾总科（Hepialoidea），是鳞翅目种低等类群。
我园协同进化组曹永强博士在导师杨大荣研究员的指导下，通过对云南蝠蛾和人支蝠蛾的线粒体全基因组的测序分析，发现其基因排列与高等鳞翅目不同但与昆虫线粒体的原始排列一致，并且在所测蝠蛾属昆虫线粒体基因组中没有发现高等鳞翅目线粒体基因组共有的一些保守元件。蝠蛾属两种昆虫线粒体基因组的排列特征揭示了鳞翅目线粒体基因重排发生在蝙蝠蛾科从其他鳞翅目分离之后。这些特征增加了我们对鳞翅目线粒体基因组结构的认识，同时对研究线粒体基因组的进化特别是基因重排机制有一定的价值。
该成果以 The complete mitochondrial genomes of two ghost moths, Thitarodes renzhiensis and Thitarodes yunnanensis: the ancestral gene arrangement in Lepidoptera发表在BMC Genomics （doi:10.1186/1471-2164-13-276）上。（生物谷Bioon.com）
doi:10.1186/1471-2164-13-276
PMC:
PMID:
The complete mitochondrial genomes of two ghost moths, Thitarodes renzhiensis and Thitarodes yunnanensis: the ancestral gene arrangement in Lepidoptera
Yong-Qiang Cao, Chuan Ma, Ji-Yue Chen and Da-Rong Yang
Background Lepidoptera encompasses more than 160,000 described species that have been classified into 45-48 superfamilies. The previously determined Lepidoptera mitochondrial genomes (mitogenomes) are limited to six superfamilies of the lineage Ditrysia. Compared with the ancestral insect gene order, these mitogenomes all contain a tRNA rearrangement. To gain new insights into Lepidoptera mitogenome evolution, we sequenced the mitogenomes of two ghost moths that belong to the non-ditrysian lineage Hepialoidea and conducted a comparative mitogenomic analysis across Lepidoptera. Results The mitogenomes of Thitarodes renzhiensis and T. yunnanensis are 16,173 bp and 15,816 bp long with an A + T content of 81.28 % and 82.34 %, respectively. Both mitogenomes include 13 protein-coding genes, 22 transfer RNA genes, 2 ribosomal RNA genes, and the A + T-rich region. Different tandem repeats in the A + T-rich region mainly account for the size difference between the two mitogenomes. All the protein-coding genes start with typical mitochondrial initiation codons, except for cox1 (CGA) and nad1 (TTG) in both mitogenomes. The anticodon of trnS(AGN) in T. renzhiensis and T. yunnanensis is UCU instead of the mostly used GCU in other sequenced Lepidoptera mitogenomes. The 1,584-bp sequence from rrnS to nad2 was also determined for an unspecified ghost moth (Thitarodes sp.), which has no repetitive sequence in the A + T-rich region. All three Thitarodes species possess the ancestral gene order with trnI-trnQ-trnM located between the A + T-rich region and nad2, which is different from the gene order trnM-trnI-trnQ in all previously sequenced Lepidoptera species. The formerly identified conserved elements of Lepidoptera mitogenomes (i.e. the motif 'ATAGA' and poly-T stretch in the A + T-rich region and the long intergenic spacer upstream of nad2) are absent in the Thitarodes mitogenomes. Conclusion The mitogenomes of T. renzhiensis and T. yunnanensis exhibit unusual features compared with the previously determined Lepidoptera mitogenomes. Their ancestral gene order indicates that the tRNA rearrangement event(s) likely occurred after Hepialoidea diverged from other lepidopteran lineages. Characterization of the two ghost moth mitogenomes has enriched our knowledge of Lepidoptera mitogenomes and contributed to our understanding of the mechanisms underlying mitogenome evolution, especially gene rearrangements.
