Techer Maéva Angélique, Clémencet Johanna, Simiand Christophe, Turpin Patrick, Garnery Lionel, Reynaud Bernard, Delatte Hélène
Université de La Réunion, UMR PVBMT, La Réunion, France.
CIRAD, UMR PVBMT, Saint Pierre, La Réunion, France.
PLoS One. 2017 Dec 27;12(12):e0189234. doi: 10.1371/journal.pone.0189234. eCollection 2017.
With globalization the Western honey bee has become a nearly cosmopolitan species, but it was originally restricted to the Old World. This renowned model of biodiversity has diverged into five evolutionary lineages and several geographic "subspecies." If Apis mellifera unicolor is indubitably an African subspecies endemic to Madagascar, its relationship with honey bees from three archipelagos in the southwest Indian Ocean (SWIO) hotspot of biodiversity is misunderstood. We compared recent mtDNA diversity data to an original characterization of the nuclear diversity from honey bees in the Mascarenes and Comoros archipelagos, using 14 microsatellites, but also additional mtDNA tRNALeu-cox2 analysis. Our sampling offers the most comprehensive dataset for the SWIO populations with a total of 3,270 colonies from 10 islands compared with 855 samples from Madagascar, 113 from Africa, and 138 from Europe. Comprehensive mitochondrial screening confirmed that honey bees from La Réunion, Mauritius, and Comoros archipelagos are mainly of African origin (88.1% out of 2,746 colonies) and that coexistence with European lineages occurs only in the Mascarenes. PCA, Bayesian, and genetic differentiation analysis showed that African colonies are not significantly distinct on each island, but have diversified among islands and archipelagos. FST levels progressively decreased in significance from European and African continental populations, to SWIO insular and continental populations, and finally among islands from the same archipelago. Among African populations, Madagascar shared a nuclear background with and was most closely related to SWIO island populations (except Rodrigues). Only Mauritius Island presented clear cytoplasmic disequilibrium and genetic structure characteristic of an admixed population undergoing hybridization, in this case, between A. m. unicolor and A. m. ligustica, A. m. carnica and A. m. mellifera-like individuals. Finally, global genetic clustering analysis helped to better depict the colonization and introduction pattern of honey bee populations in these archipelagos.
随着全球化进程，西方蜜蜂已成为一种几乎遍布全球的物种，但它最初仅限于旧世界。这种著名的生物多样性模式已分化为五个进化谱系和几个地理“亚种”。如果单色蜜蜂无疑是马达加斯加特有的非洲亚种，那么它与印度洋西南部（SWIO）生物多样性热点地区三个群岛的蜜蜂之间的关系就被误解了。我们将最近的线粒体DNA多样性数据与来自马斯卡林群岛和科摩罗群岛蜜蜂核多样性的原始特征进行了比较，使用了14个微卫星，还进行了额外的线粒体DNA亮氨酸转运RNA-细胞色素氧化酶亚基2分析。我们的采样提供了SWIO种群最全面的数据集，共有来自10个岛屿的3270个蜂群，与之相比，来自马达加斯加的样本有855个，来自非洲的有113个，来自欧洲的有138个。全面的线粒体筛选证实，来自留尼汪岛、毛里求斯和科摩罗群岛的蜜蜂主要起源于非洲（2746个蜂群中的88.1%），并且与欧洲谱系的共存仅发生在马斯卡林群岛。主成分分析、贝叶斯分析和遗传分化分析表明，非洲的蜂群在每个岛屿上并没有显著差异，但在不同岛屿和群岛之间已经多样化。从欧洲和非洲大陆种群到SWIO岛屿和大陆种群，再到同一群岛内的岛屿之间，FST水平的显著性逐渐降低。在非洲种群中，马达加斯加与SWIO岛屿种群（罗德里格斯岛除外）共享核背景，并且关系最为密切。只有毛里求斯岛呈现出明显的细胞质不平衡和遗传结构，这是一个正在进行杂交的混合种群的特征，在这种情况下，是单色蜜蜂与意大利蜜蜂、卡尼鄂拉蜜蜂和类似蜜蜂的个体之间的杂交。最后，全球遗传聚类分析有助于更好地描绘这些群岛中蜜蜂种群的殖民和引入模式。
