Laboratorio de Eco-Epidemiología, Departamento de Ecología, Genética y Evolución, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Intendente Güiraldes 2160, Ciudad Universitaria, C1428EGA, Buenos Aires, Argentina.
Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), CONICET - Universidad de Buenos Aires, Buenos Aires, Argentina.
Parasitol Res. 2020 Oct;119(10):3305-3313. doi: 10.1007/s00436-020-06789-y. Epub 2020 Jul 11.
The genetic structure of natural populations offers insight into the complexities of their dynamics, information that can be relevant to vector control strategies. Microsatellites are useful neutral markers to investigate the genetic structure and gene flow in Triatoma infestans, one of the main vectors of Chagas disease in South America. Recently, a heterogeneous pyrethroid-resistant hotspot was found in the Argentine Gran Chaco, characterized by the highest levels of deltamethrin resistance found at the present time. We applied population genetics analyses to microsatellite and village data and search for associations between the genetic variability and the heterogeneous toxicological pattern previously found. We genotyped 10 microsatellite loci in 67 T. infestans from 6 villages with no, low, and high pyrethroid resistance. The most genetically diverse populations were those susceptible or with low values of resistance. In contrast, high-resistance populations had lower herozygosity and some monomorphic loci. A negative association was found between variability and resistant ratios. Global and pairwise Fs indicated significant differentiation between populations. The only susceptible population was discriminated in all the performed studies. Low-resistance populations were also differentiated by a discriminant analysis of principal components (DAPC) and were composed mostly by the same two genetic clusters according to STRUCTURE Bayesian algorithm. Individuals from the high-resistance populations were overlapped in the DAPC and shared significant proportions of a genetic cluster. These observations suggest that the resistant populations might have a common origin, although more genetic markers and samples are required to test this hypothesis more rigorously.
自然种群的遗传结构提供了对其动态复杂性的深入了解，这些信息可能与病媒控制策略有关。微卫星是研究锥虫感染的重要中性标记，锥虫感染是南美洲恰加斯病的主要病媒之一。最近，在阿根廷大查科发现了一个异质拟除虫菊酯抗性热点，其特点是目前发现的溴氰菊酯抗性水平最高。我们应用群体遗传学分析方法对微卫星和村庄数据进行了分析，并寻找先前发现的遗传变异与异质毒理学模式之间的关联。我们对来自 6 个村庄的 67 只无、低和高拟除虫菊酯抗性的锥虫感染进行了 10 个微卫星基因座的基因分型。遗传多样性最高的种群是那些对拟除虫菊酯敏感或低耐药的种群。相比之下，高耐药种群的杂合度较低，有些单态基因座。我们发现，遗传变异性与耐药比值之间存在负相关。全球和成对 Fs 表明种群间存在显著分化。在所有进行的研究中，唯一的敏感种群都被区分开来。低耐药种群也通过主成分判别分析（DAPC）进行了区分，根据 STRUCTURE 贝叶斯算法，它们主要由两个遗传聚类组成。来自高耐药种群的个体在 DAPC 中重叠，并共享一个遗传聚类的显著比例。这些观察结果表明，耐药种群可能有共同的起源，尽管需要更多的遗传标记和样本才能更严格地检验这一假设。
