Institut Hospitalo-Universitaire (IHU) Méditerranée Infection, 13005, Marseille, France.
Institut de Recherche pour le Développement (IRD), Assistance Publique-Hôpitaux de Marseille (APHM), Microbes Evolution Phylogeny and Infections (MEPHI), Aix-Marseille University, 13005, Marseille, France.
Parasit Vectors. 2022 Mar 5;15(1):73. doi: 10.1186/s13071-022-05203-z.
The human louse (Pediculus humanus) is a haematophagous ectoparasite that is intimately related to its host. It has been of great public health concern throughout human history. This louse has been classified into six divergent mitochondrial clades (A, D, B, F, C and E). As with all haematophagous lice, P. humanus directly depends on the presence of a bacterial symbiont, known as "Candidatus Riesia pediculicola", to complement their unbalanced diet. In this study, we evaluated the codivergence of human lice around the world and their endosymbiotic bacteria. Using molecular approaches, we targeted lice mitochondrial genes from the six diverged clades and Candidatus Riesia pediculicola housekeeping genes.
The mitochondrial cytochrome b gene (cytb) of lice was selected for molecular analysis, with the aim to identify louse clade. In parallel, we developed four PCR primer pairs targeting three housekeeping genes of Candidatus Riesia pediculicola: ftsZ, groEL and two regions of the rpoB gene (rpoB-1 and rpoB-2).
The endosymbiont phylogeny perfectly mirrored the host insect phylogeny using the ftsZ and rpoB-2 genes, in addition to showing a significant co-phylogenetic congruence, suggesting a strict vertical transmission and a host-symbiont co-speciation following the evolutionary course of the human louse.
Our results unequivocally indicate that louse endosymbionts have experienced a similar co-evolutionary history and that the human louse clade can be determined by their endosymbiotic bacteria.
人体虱（Pediculus humanus）是一种与宿主密切相关的吸血外寄生虫。在人类历史上，它一直是一个非常重要的公共卫生关注点。这种虱子已经被分为六个不同的线粒体支系（A、D、B、F、C 和 E）。与所有吸血虱一样，人体虱直接依赖于一种共生细菌“Candidatus Riesia pediculicola”来补充其不平衡的饮食。在这项研究中，我们评估了世界各地人体虱及其共生细菌的共进化。我们使用分子方法，针对来自六个不同支系的虱子线粒体基因和“Candidatus Riesia pediculicola”的管家基因进行了研究。
选择虱子线粒体细胞色素 b 基因（cytb）进行分子分析，目的是鉴定虱子支系。同时，我们开发了四个针对“Candidatus Riesia pediculicola”三个管家基因的 PCR 引物对：ftsZ、groEL 和 rpoB 基因的两个区域（rpoB-1 和 rpoB-2）。
共生体的系统发育与宿主昆虫的系统发育完全一致，ftsZ 和 rpoB-2 基因显示出显著的共进化一致性，表明严格的垂直传播和宿主-共生体共进化，遵循人体虱的进化过程。
我们的研究结果明确表明，虱子共生体经历了相似的共同进化历史，并且可以通过它们的共生细菌来确定人体虱的支系。
