PNAS:人类毛囊螨的进化

摘要 : 美国Bowdoin学院生物系一项研究提出，人类毛囊螨虫的遗传结构可能为人类迁移和进化提供线索。

美国Bowdoin学院生物系一项研究提出，人类毛囊螨虫的遗传结构可能为人类迁移和进化提供线索。为了理解生活在哺乳动物毛囊中并且涉及人类皮肤病的螨虫的遗传多样性，Michael Palopoli及其同事研究了采集自具有多样的地理系谱的70人的毛囊的螨虫。这项遗传分析发现了螨虫的多个世系，包括常见于欧洲裔的一个世系和最常见于亚洲、非洲和拉丁美洲系谱的三个世系。特别是这组作者发现了地理系谱在很大程度上预测了人们携带了哪种螨虫世系。即便在一个新的地理地点生活了数代人之后，这些关联性仍然存在。此外，家人和配偶比无亲缘关系的人更可能有共同的遗传变异，这提示了在传播和密切的身体接触之间的一种联系。这组作者提出，人类毛囊螨的进化反映了古代人类种群的分化，这符合人类进化起源于非洲的假说。这组作者说，这些结果提示，螨虫可能为人类进化提供一扇窗口，而研究螨虫可能阐明它们在人类健康中的作用。

原文链接：

global divergence of the human follicle mite Demodex folliculorum: Persistent associations between host ancestry and mite lineages

原文摘要：

Microscopic mites of the genus Demodex live within the hair follicles of mammals and are ubiquitous symbionts of humans, but little molecular work has been done to understand their genetic diversity or transmission. Here we sampled mite DNA from 70 human hosts of diverse geographic ancestries and analyzed 241 sequences from the mitochondrial genome of the species Demodex folliculorum. Phylogenetic analyses recovered multiple deep lineages including a globally distributed lineage common among hosts of European ancestry and three lineages that primarily include hosts of Asian, African, and Latin American ancestry. To a great extent, the ancestral geography of hosts predicted the lineages of mites found on them; 27% of the total molecular variance segregated according to the regional ancestries of hosts. We found that D. folliculorum populations are stable on an individual over the course of years and that some Asian and African American hosts maintain specific mite lineages over the course of years or generations outside their geographic region of birth or ancestry. D. folliculorum haplotypes were much more likely to be shared within families and between spouses than between unrelated individuals, indicating that transmission requires close contact. Dating analyses indicated that D. folliculorum origins may predate modern humans. Overall, D. folliculorum evolution reflects ancient human population divergences, is consistent with an out-of-Africa dispersal hypothesis, and presents an excellent model system for further understanding the history of human movement.

doi: 10.1073/PNAS.1512609112

作者：Michael F. Palipoli

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