Tracing the origin of the early wet-season Anopheles coluzzii in the Sahel

In arid environments the source of the malaria mosquito populations that re-establish soon after first rains remains a puzzle and alternative explanations have been proposed. Using genetic data, we evaluated whether the early Rainy Season (RS) population of Anopheles coluzzii is descended from the preceding late-RS generation at the same locality, consistent with dry season (DS) dormancy (aestivation), or from migrants from distant locations. Distinct predictions derived from these two hypotheses were assessed, based on variation in 738 SNPs in eleven A. coluzzii samples, including seven samples spanning two years in a Sahelian village. As predicted by the ‘local origin under aestivation hypothesis’, temporal samples from the late RS and those collected after the first rain of the following RS were clustered together, whilst larger genetic distances were found among samples spanning the RS. Likewise, multi-locus genotype composition of samples from the end of the RS were similar across ...

在干旱环境中，首次降雨后迅速重建的疟蚊种群的来源始终是一个未解谜题，学界已提出多种替代性解释。本研究借助遗传数据，对萨赫勒地区某村落的科氏按蚊（Anopheles coluzzii）雨季早期（Rainy Season, RS）种群的起源展开评估：其究竟源自同一地点此前雨季末期的种群（符合旱季（Dry Season, DS）滞育（夏蛰，aestivation）假说），还是来自异地迁入的种群。研究基于11份科氏按蚊样本中738个单核苷酸多态性位点（Single Nucleotide Polymorphisms, SNPs）的遗传变异，对这两种假说的差异化预测进行了检验；其中7份样本覆盖了该萨赫勒村落两年的采样周期。正如"基于夏蛰的本地起源假说"所预测的，雨季末期的时序样本与次年首次降雨后采集的样本聚为一类；而跨越完整雨季的样本间则呈现出更大的遗传距离。同样地，雨季末期采集样本的多位点基因型组成在跨……