Department of Medicine, William C. Gorgas Center for Geographic Medicine, University of Alabama at Birmingham, AL, USA.
J Med Entomol. 2010 Mar;47(2):144-51. doi: 10.1603/me09092.
Studies were conducted to examine the population genetic structure of Anopheles arabiensis (Patton) in Mwea Rice Irrigation Scheme and surrounding areas in Central Kenya, under different agricultural systems. This study was motivated by observed differences in malaria transmission indices of An. arabiensis within the scheme compared with adjacent nonirrigated areas. Agricultural practices can modify local microclimate and influence the number and diversity of larval habitats and in so doing may occasion subpopulation differentiation. Thirty samples from each of the three study sites were genotyped at eight microsatellite loci. Seven microsatellite loci showed high polymorphism but revealed no genetic differentiation (FST = 0.006, P = 0.312) and high gene flow (Nm = 29-101) among the three populations. Genetic bottleneck analysis showed no indication of excess heterozygosity in any of the populations. There was high frequency of rare alleles, suggesting that An. arabiensis in the study area has a high potential of responding to selective pressures from environmental changes and vector control efforts. These findings imply that An. arabiensis in the study area occurs as a single, continuous panmictic population with great ability to adapt to human-imposed selective pressures.
研究旨在检查肯尼亚中部 Mwea 水稻灌溉计划及周边地区不同农业系统下的阿拉伯按蚊（Patton）的种群遗传结构。这项研究的动机是在该计划内观察到的阿拉伯按蚊疟疾传播指数与相邻非灌溉地区的差异。农业实践可以改变当地小气候，影响幼虫栖息地的数量和多样性，从而导致亚种群分化。在三个研究地点的每一个地点抽取了 30 个样本，在 8 个微卫星基因座进行了基因分型。七个微卫星基因座表现出高度多态性，但在三个种群之间没有遗传分化（FST = 0.006，P = 0.312）和高基因流（Nm = 29-101）。遗传瓶颈分析表明，三个种群中没有任何一个种群存在过量杂合性的迹象。罕见等位基因的频率很高，这表明研究区域的阿拉伯按蚊具有很高的潜力，可以对环境变化和病媒控制工作带来的选择压力做出反应。这些发现意味着，研究区域的阿拉伯按蚊是一个单一的、连续的、混合的群体，具有很强的适应人为施加的选择压力的能力。
