Human follicular mites: Ectoparasites becoming symbionts.
Human follicular mites: Ectoparasites becoming symbionts.
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DOI：
10.1093/molbev/msac125
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发表时间：
2022-06-21
影响因子：
10.7
通讯作者：
Braig, Henk R.
中科院分区：
文献类型：
--
作者：
Smith, Gilbert;Manzano-Marin, Alejandro;Reyes-Prieto, Mariana;Antunes, Catia Sofia Ribeiro;Ashworth, Victoria;Goselle, Obed Nanjul;Jan, Abdulhalem Abdulsamad A.;Moya, Andres;Latorre, Amparo;Perotti, M. Alejandra;Braig, Henk R.
大多数人一生都在皮肤的毛囊中携带螨虫。毛囊螨是唯一持续生活在人类身上的后生动物。我们认为毛囊蠕形螨（阿卡里）代表了从伤害宿主的专性寄生虫到专性共生体的过渡阶段。在这里，我们描述了这种转变对螨的基因组和生理的深刻影响。基因组测序结果显示，该菌与宿主的永久性结合。folliculorum通过宽松的选择和遗传漂变导致了广泛的基因组减少，导致在泛节肢动物中发现的蛋白质编码基因的数量最少。共聚焦显微镜显示，这种基因丢失与细胞数量的极度减少同时发生。单个单核肌细胞足以操作形成每条行走腿的三个部分中的每一个。虽然已经假设寄生虫细胞数量的减少在发育早期开始，但我们确定了最后发育阶段（若虫）的细胞总数比终末成虫阶段的细胞总数更大，这表明减少开始于成虫或发育的最终阶段。这是节肢动物物种进化的第一步，采用还原，寄生或内共生的生活方式。体细胞核在二倍体阶段表现出复制不足。首次提出了新的眼睛结构或光感受器以及独特的人类宿主褪黑激素引导的昼夜节律。DNA修复基因的丢失加上极端的内婚可能使这种螨类走上了进化的死胡同。
Most humans carry mites in the hair follicles of their skin for their entire lives. Follicular mites are the only metazoans that continuously live on humans. We propose that Demodex folliculorum (Acari) represents a transitional stage from a host-injuring obligate parasite to an obligate symbiont. Here, we describe the profound impact of this transition on the genome and physiology of the mite. Genome sequencing revealed that the permanent host association of D. folliculorum led to an extensive genome reduction through relaxed selection and genetic drift, resulting in the smallest number of protein-coding genes yet identified among panarthropods. Confocal microscopy revealed that this gene loss coincided with an extreme reduction in the number of cells. Single uninucleate muscle cells are sufficient to operate each of the three segments that form each walking leg. While it has been assumed that the reduction of the cell number in parasites starts early in development, we identified a greater total number of cells in the last developmental stage (nymph) than in the terminal adult stage, suggesting that reduction starts at the adult or ultimate stage of development. This is the first evolutionary step in an arthropod species adopting a reductive, parasitic, or endosymbiotic lifestyle. Somatic nuclei show under-replication at the diploid stage. Novel eye structures or photoreceptors as well as a unique human host melatonin-guided day/night rhythm are proposed for the first time. The loss of DNA repair genes coupled with extreme endogamy might have set this mite species on an evolutionary dead-end trajectory.
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影响因子：
3.1
作者：
Acosta, Sharlene;Carela, Miguelina;Massey, Steven E.
通讯作者：
Massey, Steven E.
DOI：
10.1073/pnas.1421386112
发表时间：
2015-08-18
影响因子：
11.1
作者：
Campbell, Matthew A.;Van Leuven, James T.;McCutcheon, John P.
通讯作者：
McCutcheon, John P.
影响因子：
1.3
作者：
Brooke, M. de L.
通讯作者：
Brooke, M. de L.
影响因子：
2
作者：
Boehm, Claudia;Petry, Gabriele;Strube, Christina
通讯作者：
Strube, Christina
DOI：
10.1016/j.tig.2018.01.001
发表时间：
2018-05
期刊：
Trends in genetics : TIG
影响因子：
--
作者：
Blum ID;Bell B;Wu MN
通讯作者：
Wu MN