Complexities in the genetic structure of Anopheles gambiae populations in west Africa as revealed by microsatellite DNA analysis
Complexities in the genetic structure of Anopheles gambiae populations in west Africa as revealed by microsatellite DNA analysis
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DOI：
10.1073/pnas.95.24.14260
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发表时间：
1998-11-24
影响因子：
11.1
通讯作者：
Taylor, CE
中科院分区：
文献类型：
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作者：
Lanzaro, GC;Touré, YT;Taylor, CE
冈比亚按蚊的染色体形式，被赋予非正式名称巴马科、莫普提和萨凡纳，已通过2号染色体上存在或不存在4个旁着丝粒倒位来识别。对同域分布中出现这些形式的位点的核型频率的研究表明，这些形式代表了种。我们进行了一项研究的遗传结构的人口的一个。来自西非马里两个村庄的冈比亚。每个地点的种群由巴马科型和莫普提型以及兄弟种阿拉伯按蚊组成。一些微卫星已被物理映射到多线染色体上，使得有可能根据它们相对于用于定义形式的倒位的位置来选择基因座。我们发现，在2号染色体上的所有位点的染色体形式不同，但有几个不同的位点上的其他染色体。地理差异很小。基因流似乎在基因组内的不同区域之间变化，在2号染色体上最低，可能是由于倒位的搭便车。我们的结论是，大多数观察到的染色体形式之间的遗传差异可以解释的力量，不需要涉及生殖隔离，虽然生殖隔离不排除。我们发现低水平的基因流之间的兄弟物种冈比亚按蚊和阿拉伯按蚊，类似于估计的基础上观察到的频率在自然种群中的杂交核型。
Chromosomal forms of Anopheles gambiae, given the informal designations Bamako, Mopti, and Savannah, have been recognized by the presence or absence of four paracentric inversions on chromosome 2, Studies of karyotype frequencies at sites where the forms occur in sympatry have led to the suggestion that these forms represent species. We conducted a study of the genetic structure of populations of An. gambiae from two villages in Mali, west Africa. Populations at each site were composed of the Bamako and Mopti forms and the sibling species,Anopheles arabiensis, Karyotypes were determined for each individual mosquito and genotypes at 21 microsatellite loci determined. A number of the microsatellites have been physically mapped to polytene chromosomes, making it possible to select loci based on their position relative to the inversions used to define forms. We found that the chromosomal forms differ at all loci on chromosome 2, but there were few differences for loci on other chromosomes. Geographic variation was small. Gene flow appears to vary among different regions within the genome, being lowest on chromosome 2, probably due to hitchhiking with the inversions. We conclude that the majority of observed genetic divergence between chromosomal forms can be explained by forces that need not involve reproductive isolation, although reproductive isolation is not ruled out. We found low levels of gene flow between the sibling species Anopheles gambiae and Anopheles arabiensis, similar to estimates based on observed frequencies of hybrid karyotypes in natural populations.