Mathiopoulos K D, Lanzaro G C
Laboratory of Malaria Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
J Mol Evol. 1995 Jun;40(6):578-84. doi: 10.1007/BF00160504.
The epidemiology of malaria in Africa is complicated by the fact that its principal vector, the mosquito Anopheles gambiae, constitutes a complex of six sibling species. Each species is characterized by a unique array of paracentric inversions, as deduced by karyotypic analysis. In addition, most of the species carry a number of polymorphic inversions. In order to develop an understanding of the evolutionary histories of different parts of the genome, we compared the genetic variation of areas inside and outside inversions in two distinct inversion karyotypes of A. gambiae. Thirty-five cDNA clones were mapped on the five arms of the A. gambiae chromosomes with divisional probes. Sixteen of these clones, localized both inside and outside inversions of chromosome 2, were used as probes in order to determine the nucleotide diversity of different parts of the genome in the two inversion karyotypes. We observed that the sequence diversity inside the inversion is more than three-fold lower than in areas outside the inversion and that the degree of divergence increases gradually at loci at increasing distance from the inversion. To interpret the data we present a selectionist and a stochastic model, both of which point to a relatively recent origin of the studied inversion and may suggest differences between the evolutionary history of inversions in Anopheles and Drosophila species.
非洲疟疾的流行病学情况较为复杂，因为其主要病媒冈比亚按蚊是由六个姐妹种组成的复合体。通过核型分析推断，每个物种都有一系列独特的臂内倒位特征。此外，大多数物种还带有一些多态性倒位。为了深入了解基因组不同部分的进化历史，我们比较了冈比亚按蚊两种不同倒位核型中倒位区域内外的遗传变异情况。用分区探针将35个cDNA克隆定位在冈比亚按蚊染色体的五条臂上。其中16个克隆，既定位在2号染色体倒位区域内，也定位在其外，被用作探针，以确定这两种倒位核型中基因组不同部分的核苷酸多样性。我们观察到，倒位区域内的序列多样性比倒位区域外低三倍多，并且在距倒位区域距离增加的位点，分歧程度逐渐增加。为了解释这些数据，我们提出了一个选择主义模型和一个随机模型，这两个模型都表明所研究的倒位起源相对较近，并且可能暗示按蚊和果蝇物种倒位进化历史之间的差异。
