In 1957, an invasive and highly defensive honey bee began to spread across Brazil. In the previous year, Brazilian researchers hoped to produce a subtropical-adapted honey bee by crossing local commercial honey bees (of European origin) with a South African honey bee subspecies (Apis mellifera scutellata; an A-lineage honey bee subspecies). The resulting cross—African hybrid honey bees (AHBs)—escaped from their enclosure and spread through the Americas. Today, AHB is the most common honey bee from Northern Argentina to the Southern United States. AHBs are much more likely to sting nest intruders than managed European-derived honey bee colonies. Previous studies have explored how genetic variation contributes to differences in defense response between European-derived honey bee and AHB. Although this work demonstrated very strong genetic effects on defense response, they have yet to pinpoint which genes influence variation in defense response within AHBs, specifically. We quantified defense response for 116 colonies in Brazil and performed pooled sequencing on the most phenotypically divergent samples. We identified 65 loci containing 322 genes that were significantly associated with defense response. Loci were strongly associated with metabolic function, consistent with previous functional genomic analyses of this phenotype. Additionally, defense-associated loci had nonrandom and unexpected patterns of admixture. Defense response was not simply the product of more A-lineage honey bee ancestry as previously assumed, but rather an interaction between A-lineage and European alleles. Our results suggest that a combination of A-lineage and European alleles play roles in defensive behavior in AHBs.

中文翻译：

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巴西蜜蜂（Apis mellifera scutellata × spp.）的防御反应以复杂的混合模式为基础。

1957 年，一种具有高度防御性的入侵性蜜蜂开始在巴西蔓延。去年，巴西研究人员希望通过将当地商业蜜蜂（原产于欧洲）与南非蜜蜂亚种（Apis mellifera scutellata；A 系蜜蜂亚种）杂交，培育出适应亚热带的蜜蜂。由此产生的杂交——非洲杂交蜜蜂（AHB）——逃离了它们的围栏并传播到美洲。如今，AHB 是从阿根廷北部到美国南部最常见的蜜蜂。与受管理的欧洲蜂群相比，AHB 更有可能蜇巢入侵者。先前的研究探讨了遗传变异如何导致欧洲蜜蜂和 AHB 之间防御反应的差异。尽管这项工作证明了基因对防御反应有非常强的影响，但他们尚未具体确定哪些基因会影响 AHB 内防御反应的变化。我们量化了巴西 116 个菌落的防御反应，并对表型差异最大的样本进行了汇总测序。我们鉴定了 65 个基因座，其中包含 322 个与防御反应显着相关的基因。位点与代谢功能密切相关，与之前对该表型的功能基因组分析一致。此外，防御相关基因座具有非随机和意外的混合模式。防御反应并不像之前假设的那样简单地是更多A谱系蜜蜂血统的产物，而是A谱系和欧洲等位基因之间的相互作用。我们的结果表明，A 谱系和欧洲等位基因的组合在 AHB 的防御行为中发挥作用。