Henriques Dora, Lopes Ana R, Low Matthew, Pinto M Alice
CIMO, LA SusTEC, Instituto Politécnico de Bragança, Campus de Santa Apolónia, 5300-253, Bragança, Portugal.
Department of Ecology, Swedish University of Agricultural Sciences, 750-07, Uppsala, Sweden.
Sci Rep. 2025 Jul 12;15(1):25217. doi: 10.1038/s41598-025-08950-y.
The evolutionary trajectory of island populations can be rapidly altered by human-mediated migration, a process further exacerbated when immigrants introduce invasive parasites, creating new selective pressures. Using customised SNP panels constructed with genome-wide diagnostic loci, we describe the genetic changes in honey bee populations inhabiting the Azores archipelago. As part of a breeding initiative in the 1980s, these populations were recurrently exposed to beekeeper-mediated gene flow from a highly divergent commercial line (C lineage) until the arrival of the Varroa mite to the Azores in 2000, which prompted a honey bee importation ban. Admixture analysis revealed a spatially heterogeneous introgression landscape in the Azores. Four of the five mite-free islands (Santa Maria, São Miguel, Terceira, and São Jorge) presented negligible levels of C-lineage introgression (mean Q-value: 0.004-0.091) despite repeated C-lineage importations in the past. In contrast, the three mite-infested islands (Pico, Faial, and Flores) presented high levels of introgression (mean Q-value: 0.156-0.261). The mite-free island of Graciosa harboured the most admixed population (mean Q-value: 0.392), which is consistent with efforts to eradicate the historical population and replace it with C-lineage honey bees during the implementation of the breeding program. Bayesian inference modelling indicated that the presence of a C-lineage maternal origin and Varroa were associated with increased introgression proportions (100% posterior probability), increasing the mean Q-value by 0.049 and 0.118, respectively. Our findings indicate that these anthropogenic processes altered the historically introduced gene pool and provide a foundation for developing effective conservation strategies to protect honey bees in the Azores.
岛屿种群的进化轨迹会因人类介导的迁移而迅速改变，当移民引入入侵性寄生虫时，这一过程会进一步加剧，从而产生新的选择压力。我们使用由全基因组诊断位点构建的定制SNP面板，描述了亚速尔群岛上蜜蜂种群的遗传变化。作为20世纪80年代一项育种计划的一部分，这些种群反复受到养蜂人介导的来自高度分化的商业品系（C系）的基因流动影响，直到2000年瓦螨抵达亚速尔群岛，这促使实施了蜜蜂进口禁令。混合分析揭示了亚速尔群岛上空间异质的基因渗入格局。五个无螨岛屿中的四个（圣玛丽亚岛、圣米格尔岛、特塞拉岛和圣若热岛），尽管过去曾多次引入C系，但C系基因渗入水平可忽略不计（平均Q值：0.004 - 0.091）。相比之下，三个有螨岛屿（皮科岛、法亚尔岛和弗洛雷斯岛）呈现出高水平的基因渗入（平均Q值：0.156 - 0.261）。无螨的格拉西奥萨岛拥有最混杂的种群（平均Q值：0.392），这与在实施育种计划期间根除历史种群并用C系蜜蜂取代它的努力相一致。贝叶斯推断模型表明，C系母系起源和瓦螨的存在与基因渗入比例增加相关（后验概率为100%），分别使平均Q值增加0.049和0.118。我们的研究结果表明，这些人为过程改变了历史上引入的基因库，并为制定有效的保护策略以保护亚速尔群岛的蜜蜂提供了基础。
