Mitochondrial genomes illuminate the evolutionary history of the Western honey bee (Apis mellifera)

Western honey bees (Apis mellifera) are one of the most important pollinators of agricultural crops and wild plants. Despite the growth in the availability of sequence data for honey bees, the phylogeny of the species remains a subject of controversy. Most notably, the geographic origin of honey bees is uncertain, as are the relationships among its constituent lineages and subspecies. We aim to infer the evolutionary and biogeographical history of the honey bee from mitochondrial genomes. Here we analyse the full mitochondrial genomes of 18 A. mellifera subspecies, belonging to all major lineages, using a range of gene sampling strategies and inference models to identify factors that may have contributed to the recovery of incongruent results in previous studies. Our analyses support a northern African or Middle Eastern origin of A. mellifera. We show that the previously suggested European and Afrotropical cradles of honey bees are the result of phylogenetic error. Monophyly of the M, C, and O lineages is strongly supported, but the A lineage appears paraphyletic. A. mellifera colonised Europe through at least two pathways, across the Strait of Gibraltar and via Asia Minor.

西方蜜蜂（Apis mellifera）是农业作物与野生植物最重要的传粉昆虫类群之一。尽管蜜蜂相关序列数据的可获取性持续提升，但该物种的系统发育（phylogeny）关系仍存在诸多争议。尤为值得关注的是，蜜蜂的地理起源尚未明确，其内部各组成支系与亚种间的演化关系亦尚无定论。本研究旨在通过线粒体基因组（mitochondrial genome）解析西方蜜蜂的演化与生物地理历史。本研究针对覆盖所有主要支系的18个西方蜜蜂亚种的完整线粒体基因组展开分析，采用多种基因采样策略与系统发育推断模型，以探究导致既往研究得出不一致结果的潜在因素。分析结果支持西方蜜蜂起源于北非或中东地区。研究证实，此前提出的欧洲与非洲热带地区为蜜蜂起源地的结论，实为系统发育推断误差所致。M、C、O支系的单系性（monophyly）得到强力支持，但A支系呈现出并系（paraphyletic）特征。西方蜜蜂至少通过两条路径拓殖欧洲：一是跨越直布罗陀海峡，二是经由小亚细亚地区。