Scarpassa Vera Margarete, Conn Jan E
Coordenaçúo de Pesquisas em Entomologia, Instituto Nacional de Pesquisas da Amazônia, Manaus, AM, Brasil.
Mem Inst Oswaldo Cruz. 2007 Jun;102(3):319-27. doi: 10.1590/s0074-02762007005000045.
The population genetic structure of Anopheles darlingi, the major human malaria vector in the Neotropics, was examined using seven microsatellite loci from nine localities in central and western Amazonian Brazil. High levels of genetic variability were detected (5-25 alleles per locus; H E = 0.519-0.949). There was deviation from Hardy-Weinberg Equilibrium for 59.79% of the tests due to heterozygote deficits, while the analysis of linkage disequilibrium was significant for only two of 189 (1.05%) tests, most likely caused by null alleles. Genetic differentiation (F ST = 0.001-0.095; Nm = 4.7-363.8) indicates that gene flow is extensive among locations < 152 km apart (with two exceptions) and reduced, but not absent, at a larger geographic scale. Genetic and geographic distances were significantly correlated (R(2) = 0.893, P < 0.0002), supporting the isolation by distance (IBD) model. The overall estimate of Ne was 202.4 individuals under the linkage disequilibrium model, and 8 under the heterozygote excess model. Analysis of molecular variance showed that nearly all variation (approximately 94%) was within sample locations. The UPGMA phenogram clustered the samples geographically, with one branch including 5/6 of the state of Amazonas localities and the other branch the Acre, Rondônia, and remaining Amazonas localities. Taken together, these data suggest little genetic structure for An. darlingi from central and western Amazonian Brazil. These findings also imply that the IBD model explains nearly all of the differentiation detected. In practical terms, populations of An. darlingi at distances < 152 km should respond similarly to vector control measures, because of high gene flow.
利用来自巴西亚马逊中西部九个地点的七个微卫星位点，对新热带地区主要的人类疟疾传播媒介达林按蚊的群体遗传结构进行了研究。检测到高水平的遗传变异（每个位点5 - 25个等位基因；HE = 0.519 - 0.949）。由于杂合子缺失，59.79%的测试偏离了哈迪 - 温伯格平衡，而连锁不平衡分析在189次测试中仅有两次（1.05%）显著，最可能是由无效等位基因导致的。遗传分化（FST = 0.001 - 0.095；Nm = 4.7 - 363.8）表明，相距 < 152公里的地点间基因流广泛（有两个例外），在更大地理尺度上基因流减少但并非不存在。遗传距离与地理距离显著相关（R(2) = 0.893，P < 0.0002），支持距离隔离（IBD）模型。在连锁不平衡模型下，Ne的总体估计值为202.4个个体，在杂合子过剩模型下为8个个体。分子方差分析表明，几乎所有变异（约94%）都在样本地点内。UPGMA系统树图按地理区域对样本进行聚类划分，一个分支包括亚马逊州6个地点中的5个，另一个分支包括阿克里州、朗多尼亚州以及亚马逊州其余地点。综合来看，这些数据表明来自巴西亚马逊中西部的达林按蚊几乎没有遗传结构。这些发现还意味着IBD模型解释了几乎所有检测到的分化情况。实际上，由于基因流高，相距 < 152公里的达林按蚊种群对媒介控制措施的反应应该相似。
