Scarpassa Vera Margarete, Figueiredo Adrya da Silva, Alencar Ronildo Baiatone
Laboratório de Genética de Populações e Evolução de Mosquitos Vetores de Malária e Dengue, Coordenação de Biodiversidade, Instituto Nacional de Pesquisas da Amazônia (INPA), Manaus, Amazonas, Brazil.
Laboratório de Genética de Populações e Evolução de Mosquitos Vetores de Malária e Dengue, Coordenação de Biodiversidade, Instituto Nacional de Pesquisas da Amazônia (INPA), Manaus, Amazonas, Brazil.
Infect Genet Evol. 2015 Apr;31:312-20. doi: 10.1016/j.meegid.2015.02.007. Epub 2015 Feb 17.
Lutzomyia (Nyssomyia) anduzei has been recognized as a secondary vector of Leishmania guyanensis in the Brazilian Amazon region. Since L. anduzei is anthropophilic, co-exists in areas of high leishmaniasis transmission and has been found infected with L. guyanensis, the understanding of the vector population structure and of the process responsible for it is paramount to the vector management and control efforts. In this study we analyzed 74 and 67 sequences of the COI and Cytb loci, respectively, from mitochondrial DNA, aiming to estimate the intra-population genetic variability and population structure in six L. anduzei samples from the Brazilian Amazon region. For COI, we found 58 haplotypes, low to high (FST=0.0310-0.4128) and significant (P=0.0033) genetic structure, and reduced gene flow among populations. The haplotype network yielded many reticulations that likely resulted from hypervariability in the locus. For Cytb, we observed 27 haplotypes, low to moderate (FST=0.0077-0.1954) and nonsignificant (P>0.05) genetic structure for the majority of comparisons and extensive gene flow among populations, in line with the haplotypes network data. AMOVA analysis indicated that most of the variation occurred within populations (83.41%, 90.94%); nevertheless, there were significant differences (ΦST=0.0906-0.1659; P=0.00098; P=0.00000) among them for both loci. The Mantel test showed that the genetic structure is not associated to an isolation-by-distance (IBD) model in either of both loci. These data suggest that L. anduzei is genetically very diverse. The genetic structure lacking IBD may be due to adaptation to local habitats and the low dispersal capacity of the sandflies, and both could lead to population fragmentation and geographic isolation. These findings have important implications for epidemiology, surveillance and vector control and may be a first step in understanding the evolutionary history of this species.
卢氏白蛉（奈氏白蛉亚属）安杜泽伊种已被确认为巴西亚马逊地区圭亚那利什曼原虫的次要传播媒介。由于安杜泽伊种白蛉嗜人血，在利什曼病高传播地区共存，且已发现感染圭亚那利什曼原虫，因此了解该媒介种群结构及其形成过程对于媒介管理和控制工作至关重要。在本研究中，我们分别分析了来自线粒体DNA的COI和Cytb基因座的74个和67个序列，旨在估计巴西亚马逊地区六个安杜泽伊种白蛉样本的种群内遗传变异性和种群结构。对于COI，我们发现了58个单倍型，遗传结构从低到高（FST = 0.0310 - 0.4128）且显著（P = 0.0033），种群间基因流减少。单倍型网络产生了许多网状结构，这可能是由于该基因座的高变异性所致。对于Cytb，我们观察到27个单倍型，大多数比较的遗传结构从低到中等（FST = 0.0077 - 0.1954）且不显著（P>0.05），种群间基因流广泛，这与单倍型网络数据一致。AMOVA分析表明，大部分变异发生在种群内（分别为83.41%、90.94%）；然而，两个基因座在它们之间都存在显著差异（ΦST = 0.0906 - 0.1659；P = 0.00098；P = 0.00000）。Mantel检验表明，两个基因座的遗传结构均与距离隔离（IBD）模型无关。这些数据表明安杜泽伊种白蛉在遗传上非常多样。缺乏IBD的遗传结构可能是由于适应当地栖息地以及白蛉的低扩散能力，这两者都可能导致种群碎片化和地理隔离。这些发现对流行病学、监测和媒介控制具有重要意义，可能是了解该物种进化历史的第一步。
