Data from: Worldwide patterns of genetic differentiation imply multiple "domestications" of Aedes aegypti, a major vector of human diseases

Understanding the processes by which species colonize and adapt to human habitats is particularly important in the case of disease-vectoring arthropods. The mosquito species Aedes aegypti, a major vector of dengue and yellow fever viruses, probably originated as a wild, zoophilic species in sub-Saharan Africa, where some populations still breed in tree holes in forested habitats. Many populations of the species, however, have evolved to thrive in human habitats and to bite humans. This includes some populations within Africa as well as almost all those outside Africa. It is not clear whether all domestic populations are genetically related and represent a single ‘domestication’ event, or whether association with human habitats has developed multiple times independently within the species. To test the hypotheses above, we screened 24 worldwide population samples of Ae. aegypti at 12 polymorphic microsatellite loci. We identified two distinct genetic clusters: one included all domestic populations outside of Africa and the other included both domestic and forest populations within Africa. This suggests that human association in Africa occurred independently from that in domestic populations across the rest of the world. Additionally, measures of genetic diversity support Ae. aegypti in Africa as the ancestral form of the species. Individuals from domestic populations outside Africa can reliably be assigned back to their population of origin, which will help determine the origins of new introductions of Ae. aegypti.

探究物种定居并适应人类栖息地的过程，对于病媒节肢动物（disease-vectoring arthropods）而言具有尤为重要的研究价值。埃及伊蚊（Aedes aegypti）是登革热与黄热病病毒的主要传播媒介，其起源为栖息于撒哈拉以南非洲森林树洞中的野生嗜动物（zoophilic）物种，目前该区域仍有部分种群保留此生存习性。然而，该物种的诸多种群已演化出适应人类栖息地、偏好叮咬人类的特征，这一现象不仅见于非洲境内的部分种群，更覆盖了非洲以外的几乎所有种群。目前学界仍未明确：所有家养种群是否均具有遗传亲缘关系，仅代表单次“驯化”事件；抑或是该物种与人类栖息地的共生关系已在物种内独立发生多次。为验证上述假说，我们对全球24份埃及伊蚊种群样本的12个多态微卫星位点（polymorphic microsatellite loci）进行了基因分型筛查。研究结果鉴定出两个显著分化的遗传聚类簇（genetic clusters）：其一包含非洲以外的所有家养种群，其二则囊括非洲境内的家养种群与野生森林种群。这一结果表明，非洲境内种群与人类的共生关系，其演化路径独立于全球其他地区的家养种群。此外，遗传多样性分析指标进一步支持非洲境内的埃及伊蚊为该物种的祖先类群。非洲以外的家养种群个体可被准确回溯至其起源种群，这将有助于追溯埃及伊蚊新入侵种群的来源。