The University of Edinburgh, The Kings Buildings, Ashworth Laboratories, Institute of Evolutionary Biology, West Mains Road, EH9 3JT, Edinburgh, UK.
Mol Ecol. 2010 Dec;19(23):5126-39. doi: 10.1111/j.1365-294X.2010.04833.x. Epub 2010 Oct 29.
Acacias across Africa have enormous ecological and economic importance, yet their population genetics are poorly studied. We used seven microsatellite loci to investigate spatial genetic structure and to identify potential ecological and geographic barriers to dispersal in the widespread acacia, Senegalia (Acacia) mellifera. We quantified variation among 791 individuals from 28 sampling locations, examining patterns at two spatial scales: (i) across Kenya including the Rift Valley, and (ii) for a local subset of 11 neighbouring locations on Mpala Ranch in the Laikipia plateau. Our analyses recognize that siblings can often be included in samples used to measure population genetic structure, violating fundamental assumptions made by these analyses. To address this potential problem, we maximized genetic independence of samples by creating a sibship-controlled data set that included only one member of each sibship and compared the results obtained with the full data set. Patterns of genetic structure and barriers to gene flow were essentially similar when the two data sets were analysed. Five well-defined geographic regions were identified across Kenya within which gene flow was localized, with the two strongest barriers to dispersal splitting the Laikipia Plateau of central Kenya from the Western and Eastern Rift Valley. At a smaller scale, in the absence of geographic features, regional habitat gradients appear to restrict gene flow significantly. We discuss the implications of our results for the management of this highly exploited species.
非洲金合欢具有巨大的生态和经济重要性，但它们的种群遗传学研究却很少。我们使用了七个微卫星位点来研究广泛分布的金合欢属（Acacia mellifera）的空间遗传结构，并确定潜在的生态和地理扩散障碍。我们对来自 28 个采样地点的 791 个个体进行了量化，在两个空间尺度上检验了变异模式：（i）在肯尼亚（包括裂谷）范围内，以及（ii）在 Laikipia 高原的 Mpala 牧场的 11 个相邻局部地点的一个局部子集中。我们的分析认识到，在测量种群遗传结构的样本中，通常可以包含兄弟姐妹，这违反了这些分析的基本假设。为了解决这个潜在的问题，我们通过创建一个仅包含每个兄弟姐妹中的一个成员的亲子关系控制数据集，最大限度地提高了样本的遗传独立性，并比较了使用完整数据集和亲子关系控制数据集得到的结果。当分析两个数据集时，遗传结构和基因流动障碍的模式基本相似。在肯尼亚境内确定了五个定义明确的地理区域，在这些区域内基因流动是本地化的，两个最强的扩散障碍将肯尼亚中部的莱基皮亚高原与西部和东部裂谷分开。在较小的尺度上，在没有地理特征的情况下，区域生境梯度似乎显著限制了基因流动。我们讨论了我们的结果对管理这种高度开发物种的影响。
