Data from: Laboratory rearing of Anopheles arabiensis: impact on genetic variability and implications for Sterile Insect Technique (SIT) based mosquito control in northern Sudan

Background: Mosquito colony populations often show significant changes in their population genetic make-up compared to the field populations that were used as founding source. Most of the changes that have been reported are indicators of depletion in the overall genetic diversity of the colony populations. The Sterile Insect Techniques programme of mosquito control that is underway in Northern Sudan uses sterilized males produced from a laboratory-maintained colony population. The genetic diversity of an advanced generation of this colony population was quantitatively assessed and compared to the field population from which the colony was derived. Methods: Anopheles arabiensis mosquito samples from the 13th generation of the colony, and from the locality that was the source of the first generation of the colony, were genotyped at 11 microsatellite loci distributed throughout the species’ genome. Standard population genetic analyses were carried out to quantify and compare their population genetic make-up and diversities. Results: The colony samples showed significant reduction in the total number of alleles, the numbers of rare and private alleles, and the fractions of heterozygote individuals at all the loci. The pattern of change is consistent with the expected effect of the use of a small number of mosquitoes when the colony was established. Departure from Hardy–Weinberg equilibrium in the direction of homozygote excess was observed at some loci and attributed to the presence of null-alleles. Conclusions: This study highlights the need for broad sampling when initiating colony populations and for ongoing assessment of the population genetic make-up of colony populations. Previous assessments of survivorship, dispersive behaviour and swarm formation indicate that the inbreeding and reduced genetic variability reported in this study may not have had direct fitness consequences yet. However, noting the lessons learned in other SIT programmes about the impact of colonization on male sexual behaviour and longevity, as well as other inbreeding related adverse effects, a systematic investigation of these potential effects is recommended because they have direct impact on the ultimate success of the programme.背景：相较于作为建群来源的野外种群，实验室饲养的蚊子种群往往会出现显著的种群遗传组成变化，已报道的多数此类变化均提示种群整体遗传多样性出现衰减。苏丹北部正在实施的蚊虫防控昆虫不育技术（Sterile Insect Techniques, SIT）项目，其所用的绝育雄虫均来自实验室维持的种群。本研究对该种群的高世代个体的遗传多样性进行了定量评估，并与该种群的原始建群野外种群进行对比。 方法：本研究针对阿拉伯按蚊（Anopheles arabiensis），分别采集该实验室种群第13代的样本，以及该种群建群初代的来源地野外样本，对分布于该物种全基因组的11个微卫星位点进行基因分型。随后采用标准种群遗传学分析方法，对二者的种群遗传组成与遗传多样性进行定量分析与比较。 结果：实验室种群样本在所有检测位点上均表现出等位基因总数、稀有等位基因与私有等位基因数量，以及杂合个体比例的显著降低。这一变化模式与建群时使用少量蚊虫所预期的效应相符。部分位点出现了向纯合子过剩方向偏离的哈迪-温伯格平衡（Hardy–Weinberg equilibrium, HWE）现象，该现象可归因于无效等位基因（null-alleles）的存在。 结论：本研究强调，在建立实验室种群时需进行大范围采样，并需持续监测实验室种群的遗传组成。此前针对存活率、扩散行为与婚飞行为的相关评估显示，本研究报道的近交与遗传多样性降低现象，目前尚未对适合度产生直接影响。但鉴于其他昆虫不育技术项目已证实建群过程会影响雄虫的性行为与寿命，且存在其他与近交相关的不良效应，因此建议针对这些潜在影响开展系统性研究，因其直接关系到该项目的最终成效。