1Department of Molecular Biology and Biotechnology, Pan African University Institute for Basic Sciences, Technology and Innovation, Nairobi, Kenya.
2Kenya Forestry Research Institute, Nairobi, Kenya.
Am J Trop Med Hyg. 2020 Dec 28;104(3):917-927. doi: 10.4269/ajtmh.20-0774.
Tsetse flies of the palpalis group, particularly Glossina fuscipes, are the main vectors of human African trypanosomiasis or sleeping sickness in Congo-Brazzaville. They transmit the deadly human parasite, Trypanosoma brucei gambiense and other trypanosomes that cause animal trypanosomiasis. Knowledge on diversity, population structure, population size, and gene flow is a prerequisite for designing effective tsetse control strategies. There is limited published information on these parameters including migration patterns of G. fuscipes in Congo-Brazzaville. We genotyped 288 samples of G. fuscipes from Bomassa (BMSA), Bouemba (BEMB), and Talangai (TLG) locations at 10 microsatellite loci and determined levels of genetic diversity, differentiation, structuring, and gene flow among populations. We observed high genetic diversity in all three localities. Mean expected heterozygosity was 0.77 ± 0.04, and mean allelic richness was 11.2 ± 1.35. Deficiency of heterozygosity was observed in all populations with positive and significant F IS values (0.077-0.149). Structure analysis revealed three clusters with genetic admixtures, evidence of closely related but potentially different taxa within G. fuscipes. Genetic differentiation indices were low but significant (F ST = 0.049, P < 0.05), indicating ongoing gene flow countered with a stronger force of drift. We recorded significant migration from all the three populations, suggesting exchange of genetic information between and among locations. Ne estimates revealed high and infinite population sizes in BEMB and TLG. These critical factors should be considered when planning area-wide tsetse control interventions in the country to prevent resurgence of tsetse from relict populations and/or reinvasion of cleared habitats.
采采蝇属中的舌蝇，特别是棕尾褐麻蝇，是刚果（布）的人类非洲锥虫病或昏睡病的主要传播媒介。它们传播致命的人体寄生虫，即冈比亚锥虫和其他引起动物锥虫病的锥虫。多样性、种群结构、种群规模和基因流的知识是设计有效采采蝇控制策略的前提。关于这些参数，包括刚果（布）棕尾褐麻蝇的迁移模式，发表的信息有限。我们在 10 个微卫星基因座对来自博马萨（BMSA）、布姆巴（BEMB）和塔兰加（TLG）的 288 个棕尾褐麻蝇样本进行了基因分型，并确定了种群间的遗传多样性、分化、结构和基因流水平。我们观察到所有三个地点的遗传多样性都很高。平均预期杂合度为 0.77 ± 0.04，平均等位基因丰富度为 11.2 ± 1.35。所有种群都观察到杂合子缺失，FIS 值为正且显著（0.077-0.149）。结构分析显示存在三个聚类群，存在棕尾褐麻蝇内亲缘关系密切但潜在不同的类群的遗传混合。遗传分化指数较低但显著（FST=0.049，P<0.05），表明正在发生基因流，但漂移的力量更强。我们记录到所有三个种群都有显著的迁移，表明了各地点之间和之间遗传信息的交换。Ne 估计表明，BEMB 和 TLG 的种群规模很大且无限。在规划该国的采采蝇全地区控制干预措施时，应该考虑到这些关键因素，以防止残余种群的采采蝇再次出现和/或已清除栖息地的再次入侵。
