Powell J R, Petrarca V, della Torre A, Caccone A, Coluzzi M
Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT 06511, USA.
Parassitologia. 1999 Sep;41(1-3):101-13.
We review here what is known about the population structure and evolutionary dynamics of members of the Anopheles gambiae complex with emphasis on the situation in West Africa. First, the importance of the 2nd chromosome inversion polymorphism is demonstrated especially in adaptation to levels of aridity, a major environmental variable in Africa. This affects the distribution of karyotypes on both a macro- and micro-geographic scale as well as temporally. Such differentiation leads to karyotypes being differentially effective transmitters of malaria and differentially susceptible to indoor residual spraying of insecticides. Second, we review the evidence that cryptic taxa, especially in An. gambiae s.s., exist. This observation stems from both karyotype studies and molecular studies. It is abundantly clear that West African populations of An. gambiae s.s. are often not panmictic units, with premating factors evidently acting to maintain distinct genetic forms. Third, we review phylogenetic studies that have revealed the presence of introgression between the two most important vectors, An. gambiae and An. arabiensis. This is most evident for the 2nd chromosome inversions. This interpretation of phylogenetic data is consistent with a direct laboratory study indicating inversions in this chromosome are stably maintained in back-crossed populations. All of this information has led to the view that members of the An. gambiae complex are highly variable with an abundance of adaptive genetic variation. This presents a significant challenge to vector control programs designed to reduce malaria in sub-Saharan Africa.
我们在此回顾关于冈比亚按蚊复合体成员的种群结构和进化动态的已知信息，重点关注西非的情况。首先，证明了第2号染色体倒位多态性的重要性，特别是在适应干旱程度方面，干旱是非洲的一个主要环境变量。这在宏观和微观地理尺度以及时间上都会影响核型的分布。这种分化导致核型在传播疟疾方面的有效性不同，以及对室内残留喷洒杀虫剂的易感性不同。其次，我们回顾了存在隐性分类群的证据，特别是在冈比亚按蚊指名亚种中。这一观察结果源于核型研究和分子研究。很明显，冈比亚按蚊指名亚种的西非种群通常不是随机交配的群体，交配前因素显然在维持不同的遗传形式方面起作用。第三，我们回顾了系统发育研究，这些研究揭示了两个最重要的病媒——冈比亚按蚊和阿拉伯按蚊之间存在基因渗入。这在第2号染色体倒位方面最为明显。对系统发育数据的这种解释与一项直接的实验室研究一致，该研究表明该染色体上的倒位在回交群体中能稳定维持。所有这些信息都导致了这样一种观点，即冈比亚按蚊复合体的成员具有高度变异性，存在大量适应性遗传变异。这给旨在减少撒哈拉以南非洲疟疾的病媒控制项目带来了重大挑战。
