Wang-Sattler Rui, Blandin Stephanie, Ning Ye, Blass Claudia, Dolo Guimogo, Touré Yeya T, delle Torre Alessandra, Lanzaro Gregory C, Steinmetz Lars M, Kafatos Fotis C, Zheng Liangbiao
European Molecular Biology Laboratory, Heidelberg, Germany.
PLoS One. 2007 Nov 28;2(11):e1249. doi: 10.1371/journal.pone.0001249.
Attempts over the last three decades to reconstruct the phylogenetic history of the Anopheles gambiae species complex have been important for developing better strategies to control malaria transmission.
We used fingerprint genotyping data from 414 field-collected female mosquitoes at 42 microsatellite loci to infer the evolutionary relationships of four species in the A. gambiae complex, the two major malaria vectors A. gambiae sensu stricto (A. gambiae s.s.) and A. arabiensis, as well as two minor vectors, A. merus and A. melas.
We identify six taxonomic units, including a clear separation of West and East Africa A. gambiae s.s. S molecular forms. We show that the phylogenetic relationships vary widely between different genomic regions, thus demonstrating the mosaic nature of the genome of these species. The two major malaria vectors are closely related and closer to A. merus than to A. melas at the genome-wide level, which is also true if only autosomes are considered. However, within the Xag inversion region of the X chromosome, the M and two S molecular forms are most similar to A. merus. Near the X centromere, outside the Xag region, the two S forms are highly dissimilar to the other taxa. Furthermore, our data suggest that the centromeric region of chromosome 3 is a strong discriminator between the major and minor malaria vectors.
Although further studies are needed to elucidate the basis of the phylogenetic variation among the different regions of the genome, the preponderance of sympatric admixtures among taxa strongly favor introgression of different genomic regions between species, rather than lineage sorting of ancestral polymorphism, as a possible mechanism.
在过去三十年中，为重建冈比亚按蚊物种复合体的系统发育历史所做的努力，对于制定更好的控制疟疾传播策略具有重要意义。
我们使用了从414只野外采集的雌性蚊子的指纹基因分型数据，这些数据来自42个微卫星位点，以推断冈比亚按蚊复合体中四个物种的进化关系，这四个物种分别是两种主要的疟疾传播媒介——冈比亚按蚊指名亚种（A. gambiae s.s.）和阿拉伯按蚊（A. arabiensis），以及两种次要传播媒介——梅氏按蚊（A. merus）和密氏按蚊（A. melas）。
我们识别出六个分类单元，包括西非和东非冈比亚按蚊指名亚种的S分子型的明显分离。我们表明，不同基因组区域之间的系统发育关系差异很大，从而证明了这些物种基因组的镶嵌性质。在全基因组水平上，这两种主要的疟疾传播媒介关系密切，且比密氏按蚊更接近梅氏按蚊，如果仅考虑常染色体，情况也是如此。然而，在X染色体的Xag倒位区域内，M和两种S分子型与梅氏按蚊最为相似。在Xag区域之外的X染色体着丝粒附近，两种S型与其他分类群高度不同。此外，我们的数据表明，3号染色体的着丝粒区域是主要和次要疟疾传播媒介之间的一个强有力的区分因素。
尽管需要进一步研究来阐明基因组不同区域之间系统发育变异的基础，但分类群之间同域混合的优势强烈支持物种间不同基因组区域的渐渗，而不是祖先多态性的谱系分选，作为一种可能的机制。
