BACKGROUND In recent years, the Asian tiger mosquito Aedes albopictus has emerged as a species of major medical concern following its global expansion and involvement in many arbovirus outbreaks. On Réunion Island, Ae. albopictus was responsible for a large chikungunya outbreak in 2005-2006 and more recently an epidemic of dengue which began at the end of 2017 and is still ongoing at the time of writing. This dengue epidemic has seen a high number of human cases in south and west coastal regions, while few cases have been reported in the north and east of the island. To better understand the role of mosquito populations in such spatial patterns of dengue virus transmission in Réunion Island, we examined the genetic diversity and population structure of Ae. albopictus sampled across the island. RESULTS Between November 2016 and March 2017, a total of 564 mosquitoes were collected from 19 locations in three main climatic regions (West, East and Center) of Réunion Island and were genotyped using 16 microsatellite loci. A high genetic diversity was observed with 2-15 alleles per locus and the average number of alleles per population varying between 4.70-5.90. Almost all FIS values were significantly positive and correlated to individual relatedness within populations using a hierarchical clustering approach based on principal components analyses (HCPC). However, the largest part of genetic variance was among individuals within populations (97%) while only 3% of genetic variance was observed among populations within regions. Therefore, no distinguishable population structure or isolation by distance was evidenced, suggesting high rates of gene flow at the island scale. CONCLUSIONS Our results show high genetic diversity but no genetic structure of Ae. albopictus populations in Réunion Island thus reflecting frequent movements of mosquitoes between populations probably due to human activity. These data should help in the understanding of Ae. albopictus vector capacity and the design of effective mosquito control strategies.

中文翻译：

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留尼汪岛的白纹伊蚊种群遗传多样性高，但没有地理结构。

背景技术近年来，亚洲虎蚊白纹伊蚊（Aedes albopictus）在其全球扩张和参与许多虫媒病毒爆发之后已经成为一种主要的医学关注物种。在AE留尼汪岛。albopictus造成了2005-2006年的一次大规模基孔肯雅热疫情，最近是登革热的流行病，这种流行病始于2017年底，在撰写本文时仍在持续。这种登革热流行在南部和西部沿海地区看到了许多人间病例，而在该岛的北部和东部则鲜有报道。为了更好地了解蚊子种群在留尼汪岛这种登革热病毒传播的空间格局中的作用，我们研究了Ae的遗传多样性和种群结构。整个岛屿都采样了白化病。结果从2016年11月到2017年3月，在留尼汪岛的三个主要气候区（西部，东部和中部）的19个地点收集了564只蚊子，并使用16个微卫星基因座对它们进行了基因分型。观察到高遗传多样性，每个基因座有2-15个等位基因，每个群体的平均等位基因数量在4.70-5.90之间变化。使用基于主成分分析（HCPC）的分层聚类方法，几乎​​所有FIS值均显着为正，并与人群中的个人相关性相关。但是，遗传变异的最大部分是在人群中的个体之间（97％），而在区域内的人群中仅观察到了3％的遗传变异。因此，没有证据表明有明显的种群结构或按距离隔离，这表明在岛屿规模的基因流动率很高。结论我们的结果表明Ae具有较高的遗传多样性，但没有遗传结构。留尼汪岛上的白带虫种群因此反映出蚊子在种群之间的频繁移动可能是由于人类活动造成的。这些数据应有助于理解Ae。白化病媒介能力和有效的灭蚊策略设计。