Abstract：
BACKGROUND: Fleas (Insecta: Siphonaptera) are obligatory hematophagous ectoparasites of humans and animals and serve as vectors of many disease-causing agents. Despite past and current research efforts on fleas due to their medical and veterinary importance, correct identification and robust phylogenetic analysis of these ectoparasites have often proved challenging.
METHODS: We decoded the complete mitochondrial (mt) genome of the human flea Pulex irritans and nearly complete mt genome of the dog flea Ctenocephalides canis, and subsequently used this information to reconstruct the phylogeny of fleas among Endopterygota insects.
RESULTS: The complete mt genome of P. irritans was 20,337 bp, whereas the clearly sequenced coding region of the C. canis mt genome was 15,609 bp. Both mt genomes were found to contain 37 genes, including 13 protein-coding genes, 22 transfer RNA genes and two ribosomal RNA genes. The coding region of the C. canis mt genome was only 93.5% identical to that of the cat flea C. felis, unequivocally confirming that they are distinct species. Our phylogenomic analyses of the mt genomes showed a sister relationship between the order Siphonaptera and orders Diptera + Mecoptera + Megaloptera + Neuroptera and positively support the hypothesis that the fleas in the order Siphonaptera are monophyletic.
CONCLUSIONS: Our results demonstrate that the mt genomes of P. irritans and C. canis are different. The phylogenetic tree shows that fleas are monophyletic and strongly support an order-level objective. These mt genomes provide novel molecular markers for studying the taxonomy and phylogeny of fleas in the future.
METHODS: We decoded the complete mitochondrial (mt) genome of the human flea Pulex irritans and nearly complete mt genome of the dog flea Ctenocephalides canis, and subsequently used this information to reconstruct the phylogeny of fleas among Endopterygota insects.
RESULTS: The complete mt genome of P. irritans was 20,337 bp, whereas the clearly sequenced coding region of the C. canis mt genome was 15,609 bp. Both mt genomes were found to contain 37 genes, including 13 protein-coding genes, 22 transfer RNA genes and two ribosomal RNA genes. The coding region of the C. canis mt genome was only 93.5% identical to that of the cat flea C. felis, unequivocally confirming that they are distinct species. Our phylogenomic analyses of the mt genomes showed a sister relationship between the order Siphonaptera and orders Diptera + Mecoptera + Megaloptera + Neuroptera and positively support the hypothesis that the fleas in the order Siphonaptera are monophyletic.
CONCLUSIONS: Our results demonstrate that the mt genomes of P. irritans and C. canis are different. The phylogenetic tree shows that fleas are monophyletic and strongly support an order-level objective. These mt genomes provide novel molecular markers for studying the taxonomy and phylogeny of fleas in the future.
摘要：
背景：跳蚤（昆虫纲：Siphonaptera）是人类和动物的强制性食血性体外寄生虫，可作为许多致病因子的载体。尽管过去和现在对跳蚤的研究努力，由于它们的医学和兽医的重要性，这些体外寄生虫的正确识别和可靠的系统发育分析通常被证明具有挑战性。
方法：我们解码了人类跳蚤的完整线粒体（mt）基因组和狗跳蚤Ctenocephalidescanis的几乎完整的mt基因组，并随后使用此信息重建了Endopterygota昆虫中跳蚤的系统发育。
结果：P.irritans的完整mt基因组为20,337bp，而C.canismt基因组的清晰测序编码区为15,609bp。发现两个mt基因组都包含37个基因，包括13个蛋白质编码基因，22个转移RNA基因和两个核糖体RNA基因。C.canismt基因组的编码区与猫跳蚤C.felis的编码区仅93.5％相同，明确确认它们是不同的物种。我们对mt基因组的系统基因组分析显示，Siphonaptera目与Diptera，Mecoptera，Megaloptera，Neuroptera目之间存在姐妹关系，并积极支持以下假设：Siphonaptera目的跳蚤是单系的。
结论：我们的结果表明P.irritans和C.canis的mt基因组是不同的。系统发育树表明跳蚤是单系的，并强烈支持有序水平的目标。这些mt基因组为将来研究跳蚤的分类学和系统发育提供了新的分子标记。
方法：我们解码了人类跳蚤的完整线粒体（mt）基因组和狗跳蚤Ctenocephalidescanis的几乎完整的mt基因组，并随后使用此信息重建了Endopterygota昆虫中跳蚤的系统发育。
结果：P.irritans的完整mt基因组为20,337bp，而C.canismt基因组的清晰测序编码区为15,609bp。发现两个mt基因组都包含37个基因，包括13个蛋白质编码基因，22个转移RNA基因和两个核糖体RNA基因。C.canismt基因组的编码区与猫跳蚤C.felis的编码区仅93.5％相同，明确确认它们是不同的物种。我们对mt基因组的系统基因组分析显示，Siphonaptera目与Diptera，Mecoptera，Megaloptera，Neuroptera目之间存在姐妹关系，并积极支持以下假设：Siphonaptera目的跳蚤是单系的。
结论：我们的结果表明P.irritans和C.canis的mt基因组是不同的。系统发育树表明跳蚤是单系的，并强烈支持有序水平的目标。这些mt基因组为将来研究跳蚤的分类学和系统发育提供了新的分子标记。
