Nuclear Genetic Diversity in Human Lice (Pediculus humanus) Reveals Continental Differences and High Inbreeding among Worldwide Populations
Nuclear Genetic Diversity in Human Lice (Pediculus humanus) Reveals Continental Differences and High Inbreeding among Worldwide Populations
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DOI：
10.1371/journal.pone.0057619
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发表时间：
2013-02-27
期刊：
影响因子：
3.7
通讯作者：
Reed, David L.
中科院分区：
文献类型：
--
作者：
Ascunce, Marina S.;Toups, Melissa A.;Reed, David L.
了解寄生虫的进化对基础和应用进化生物学都很重要。了解寄生虫种群的遗传结构对于我们预测感染如何通过宿主种群传播以及设计有效的控制方法至关重要。然而，对大多数人类寄生虫的遗传结构知之甚少，包括人类虱子（Pediculus humanus）。该物种由两种生态型组成：头虱（Pediculus humanus capitis De Geer）和衣虱（Pediculus humanus Linnaeus）。每年有数亿头虱感染影响儿童，而且这个数字还在上升，部分原因是对杀虫剂的抗药性增加。衣服上的虱子主要影响无家可归者和难民营的人口，虽然它们没有头虱那么普遍，但医疗后果更严重，因为它们携带致命的细菌病原体。在这项研究中，我们提出了第一次评估的人虱种群的遗传结构，通过分析15个新开发的微卫星位点在93人虱从11个地点在世界四个地区的核遗传变异。这两种生态型表现出杂合子赤字相对于哈代-温伯格平衡和高近交值，预期的模式，其寄生生活史。贝叶斯聚类分析将虱子分配到四个不同的地理结构的遗传簇。虱子种群中基因流动水平较低，表明虱子杀虫剂抗性的进化很可能受到当地选择压力的影响，这凸显了根据种群特定基因组成和进化历史制定控制策略的重要性。我们的微卫星标记小组提供了强有力的数据，不仅可以调查虱子的生态和进化过程，还可以调查人类宿主的生态和进化过程，因为虱子和人类之间存在长期的共同进化关系。
Understanding the evolution of parasites is important to both basic and applied evolutionary biology. Knowledge of the genetic structure of parasite populations is critical for our ability to predict how an infection can spread through a host population and for the design of effective control methods. However, very little is known about the genetic structure of most human parasites, including the human louse (Pediculus humanus). This species is composed of two ecotypes: the head louse (Pediculus humanus capitis De Geer), and the clothing (body) louse (Pediculus humanus humanus Linnaeus). Hundreds of millions of head louse infestations affect children every year, and this number is on the rise, in part because of increased resistance to insecticides. Clothing lice affect mostly homeless and refugee-camp populations and although they are less prevalent than head lice, the medical consequences are more severe because they vector deadly bacterial pathogens. In this study we present the first assessment of the genetic structure of human louse populations by analyzing the nuclear genetic variation at 15 newly developed microsatellite loci in 93 human lice from 11 sites in four world regions. Both ecotypes showed heterozygote deficits relative to Hardy-Weinberg equilibrium and high inbreeding values, an expected pattern given their parasitic life history. Bayesian clustering analyses assigned lice to four distinct genetic clusters that were geographically structured. The low levels of gene flow among louse populations suggested that the evolution of insecticide resistance in lice would most likely be affected by local selection pressures, underscoring the importance of tailoring control strategies to population-specific genetic makeup and evolutionary history. Our panel of microsatellite markers provides powerful data to investigate not only ecological and evolutionary processes in lice, but also those in their human hosts because of the long-term coevolutionary association between lice and humans.