Department of Molecular Biotechnology, Ghent University (UGent), Coupure Links 653, B-9000 Ghent, Belgium.
Am J Bot. 2009 May;96(5):950-7. doi: 10.3732/ajb.0800266. Epub 2009 Apr 16.
This study evaluates the spatial genetic structure of baobab (Adansonia digitata) populations from West African agroforestry systems at different geographical scales using AFLP fingerprints. Eleven populations from four countries (Benin, Ghana, Burkina Faso, and Senegal) had comparable levels of genetic diversity, although the two populations in the extreme west (Senegal) had less diversity. Pairwise F(ST) ranged from 0.02 to 0.28 and increased with geographic distance, even at a regional scale. Gene pools detected by Bayesian clustering seem to be a byproduct of the isolation-by-distance pattern rather than representing actual discrete entities. The organization of genetic diversity appears to result essentially from spatially restricted gene flow, with some influences of human seed exchange. Despite the potential for relatively long-distance pollen and seed dispersal by bats within populations, statistically significant spatial genetic structuring within populations (SGS) was detected and gave a mean indirect estimate of neighborhood size of ca. 45. This study demonstrated that relatively high levels of genetic structuring are present in baobab at both large and within-population level, which was unexpected in regard to its dispersal by bats and the influence of human exchange of seeds. Implications of these results for the conservation of baobab populations are discussed.
本研究采用 AFLP 指纹图谱，在不同地理尺度上评估了来自西非农林复合系统的猴面包树（Adansonia digitata）种群的空间遗传结构。来自四个国家（贝宁、加纳、布基纳法索和塞内加尔）的 11 个种群具有相当水平的遗传多样性，尽管最西部的两个种群（塞内加尔）的多样性较低。成对的 F(ST) 范围从 0.02 到 0.28，并且随着地理距离的增加而增加，即使在区域尺度上也是如此。贝叶斯聚类检测到的基因库似乎是隔离距离模式的副产品，而不是代表实际离散实体。遗传多样性的组织似乎主要是由于空间限制的基因流，而人类的种子交换也有一定的影响。尽管蝙蝠在种群内具有相对长距离的花粉和种子散布的潜力，但在种群内检测到了具有统计学意义的空间遗传结构（SGS），并给出了大约 45 的邻居大小的间接估计值。本研究表明，在大种群和种群内水平上，猴面包树存在相对较高水平的遗传结构，这与蝙蝠的传播和人类种子交换的影响有关，这是出乎意料的。讨论了这些结果对猴面包树种群保护的影响。
