Extensive Genetic Differentiation between Homomorphic Sex Chromosomes in the Mosquito Vector, Aedes aegypti
Extensive Genetic Differentiation between Homomorphic Sex Chromosomes in the Mosquito Vector, Aedes aegypti
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DOI：
10.1093/gbe/evx171
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发表时间：
2017-09-01
影响因子：
3.3
通讯作者：
Lambrechts, Louis
中科院分区：
文献类型：
--
作者：
Fontaine, Albin;Filipovic, lgor;Lambrechts, Louis
性别决定系统的机制和进化动力学特别感兴趣的人类病原体的昆虫载体，如蚊子，因为新的控制策略的目的是将病原体传播的女性到nonbiting男性，或依赖于准确的性别鉴定不育男性的释放。在登革热和寨卡病毒的主要载体埃及伊蚊中，性别决定由显性雄性决定基因座控制，以前认为该基因座位于一个小的、非重组的性别决定区（SDR）内。在这里，我们提供的证据表明，性染色体在Ae。埃及人在比SDR大得多的区域内的男性和女性之间存在遗传差异。我们的链接年龄映射杂交未能检测到X和Y染色体之间的重组超过123 Mbp的区域（40%的物理长度）包含SDR。这一区域减少男性重组重叠一个较小的63-Mbp区域（性染色体的物理长度的20%）显示高的男性-女性遗传分化无关的野生种群从巴西和澳大利亚，并在参考实验室菌株起源于非洲。此外，性别分化的基因组区域与一个显着过量的男性到女性的杂合性，并包含一个小簇的位点与Y特异性无效等位基因一致。我们证明，性染色体之间的遗传分化足以高精度地将个体分配到正确的性别。我们还展示了如何性别之间的等位基因频率差异的数据可以用来估计基因座和性别决定基因座之间的连锁不平衡。我们的发现大规模的遗传分化之间的性染色体在Ae。埃及伊蚊为绘图和种群基因组研究以及针对性别决定途径的蚊虫控制战略奠定了新的基础。
Mechanisms and evolutionary dynamics of sex-determination systems are of particular interest in insect vectors of human pathogens like mosquitoes because novel control strategies aim to convert pathogen-transmitting females into nonbiting males, or rely on accurate sexing for the release of sterile males. In Aedes aegypti, the main vector of dengue and Zika viruses, sex determination is governed by a dominant male-determining locus, previously thought to reside within a small, nonrecombining, sex-determining region (SDR) of an otherwise homomorphic sex chromosome. Here, we provide evidence that sex chromosomes in Ae. aegypti are genetically differentiated between males and females over a region much larger than the SDR. Our link age mapping intercrosses failed to detect recombination between X and Y chromosomes over a 123-Mbp region (40% of their physical length) containing the SDR. This region of reduced male recombination overlapped with a smaller 63-Mbp region (20% of the physical length of the sex chromosomes) displaying high male-female genetic differentiation in unrelated wild populations from Brazil and Australia and in a reference laboratory strain originating from Africa. In addition, the sex-differentiated genomic region was associated with a significant excess of male-to-female heterozygosity and contained a small cluster of loci consistent with Y-specific null alleles. We demonstrate that genetic differentiation between sex chromosomes is sufficient to assign individuals to their correct sex with high accuracy. We also show how data on allele frequency differences between sexes can be used to estimate linkage disequilibrium between loci and the sex-determining locus. Our discovery of large-scale genetic differentiation between sex chromosomes in Ae. aegypti lays a new foundation for mapping and population genomic studies, as well as for mosquito control strategies targeting the sex-determination pathway.