在整个阿非利坎山地的非洲李属范围内，核遗传多样性呈发散模式，反映了非洲高地气候的多变性。
Divergent pattern of nuclear genetic diversity across the range of the Afromontane Prunus africana mirrors variable climate of African highlands.
机构信息
Federal Research and Training Centre for Forests, Natural Hazards and Landscape (BFW), Department of Forest Genetics, Hauptstraße 7, A-1140 Vienna, Austria.
出版信息
Ann Bot. 2013 Jan;111(1):47-60. doi: 10.1093/aob/mcs235.
BACKGROUND AND AIMS
Afromontane forest ecosystems share a high similarity of plant and animal biodiversity, although they occur mainly on isolated mountain massifs throughout the continent. This resemblance has long provoked questions on former wider distribution of Afromontane forests. In this study Prunus africana (one of the character trees of Afromontane forests) is used as a model for understanding the biogeography of this vegetation zone.
METHODS
Thirty natural populations from nine African countries covering a large part of Afromontane regions were analysed using six nuclear microsatellites. Standard population genetic analysis as well as Bayesian and maximum likelihood models were used to infer genetic diversity, population differentiation, barriers to gene flow, and recent and all migration among populations.
KEY RESULTS
Prunus africana exhibits strong divergence among five main Afromontane regions: West Africa, East Africa west of the Eastern Rift Valley (ERV), East Africa east of the ERV, southern Africa and Madagascar. The strongest divergence was evident between Madagascar and continental Africa. Populations from West Africa showed high similarity with East African populations west of the ERV, whereas populations east of the ERV are closely related to populations of southern Africa, respectively.
CONCLUSIONS
The observed patterns indicate divergent population history across the continent most likely associated to Pleistocene changes in climatic conditions. The high genetic similarity between populations of West Africa with population of East Africa west of the ERV is in agreement with faunistic and floristic patterns and provides further evidence for a historical migration route. Contrasting estimates of recent and historical gene flow indicate a shift of the main barrier to gene flow from the Lake Victoria basin to the ERV, highlighting the dynamic environmental and evolutionary history of the region.
背景与目的
尽管主要分布在整个非洲大陆孤立的山脉中，但非洲山地森林生态系统具有高度相似的植物和动物生物多样性。这种相似性长期以来引发了人们对曾经更广泛分布的非洲山地森林的疑问。在这项研究中，非洲李（非洲山地森林的特征树种之一）被用作理解该植被区生物地理学的模型。
方法
分析了来自非洲九个国家的 30 个自然种群，这些种群覆盖了大部分非洲山地地区，使用了六个核微卫星。标准种群遗传分析以及贝叶斯和最大似然模型用于推断遗传多样性、种群分化、基因流障碍以及种群间的近期和所有迁移。
主要结果
非洲李在五个主要的非洲山地地区表现出强烈的分化：西非、东非裂谷以西（ERV）、东非裂谷以东、南部非洲和马达加斯加。马达加斯加和非洲大陆之间的分化最为明显。来自西非的种群与东非裂谷以西的种群高度相似，而裂谷以东的种群与南部非洲的种群密切相关。
结论
观察到的模式表明，整个大陆的种群历史存在分歧，这很可能与更新世气候条件的变化有关。西非种群与东非裂谷以西的种群之间的高度遗传相似性与动物区系和植物区系模式一致，并为历史迁移路线提供了进一步的证据。近期和历史基因流的对比估计表明，主要基因流障碍已从维多利亚湖盆地转移到东非裂谷，突出了该地区动态的环境和进化历史。
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