Understanding population structure and historical demography in a conservation context: population genetics of the endangered Kirengeshoma palmata (Hydrangeaceae).
Understanding population structure and historical demography in a conservation context: population genetics of the endangered Kirengeshoma palmata (Hydrangeaceae).
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DOI：
10.3732/ajb.1400043
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发表时间：
2014-03
影响因子：
3
通讯作者：
N. Yuan;Yi Sun;H. Comes;C. Fu;Y. Qiu
中科院分区：
文献类型：
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作者：
N. Yuan;Yi Sun;H. Comes;C. Fu;Y. Qiu
研究的前提历史和当代的微进化过程都对东亚植物特有的遗传模式产生了很大的影响，但这些过程的空间和时间背景仍然知之甚少。在这里，我们研究了历史和当代基因流动和漂移对产于东中国和日本南部的多年生草本植物手掌青冈种群遗传结构的相对影响。方法我们利用9个多态微卫星基因座的数据来评估7个已知群体中6个群体的遗传多样性水平、有效种群规模以及当代和历史基因流。主要结果我们发现群体内存在高水平的近亲交配和等位基因多样性。人口之间的当代和历史迁移率都很低，对替代人口历史模型的测试强烈支持长期漂移-迁移平衡模型。我们推测人口数量在10,000-10,000年前有所下降，但未能检测到最近的下降。贝叶斯聚类将棕榈鱼种群划分为3个遗传聚类群，其中2个与中国东部两条山脉的冰川避难所假说一致。结论这些结果表明，人为碎片化对中国棕榈鱼的遗传特征影响不大。相反，由于晚更新世气候变化以及花粉和种子传播受限，过去种群规模的下降可能导致历史和当代基因流动水平较低，导致遗传漂移和近亲繁殖导致相邻山脉之间的高度遗传分化。
PREMISE OF THE STUDY Both historical and contemporary microevolutionary processes greatly influence the genetic patterns of East Asian plant endemics, but the spatial and temporal contexts of these processes remain poorly understood. Here, we investigate the relative influences of historical and contemporary gene flow and drift on the population genetic structure of Kirengeshoma palmata, a perennial herb from East China and South Japan. METHODS We used data from nine polymorphic microsatellite loci to assess the levels of genetic diversity, effective population size, and contemporary and historical gene flow for six of the seven known populations. KEY RESULTS We found high levels of inbreeding and allelic diversity within populations. Both contemporary and historical migration rates among populations were low, and a test of alternate models of population history strongly favored a model of long-term drift-migration equilibrium. We inferred declines in population size ca. 10,000-100,000 yr ago, but failed to detect recent declines. Bayesian clustering divided K. palmata populations into three genetic clusters, two of which were consistent with a glacial refugium hypothesis for two mountain ranges in East China. CONCLUSIONS These results suggest that anthropogenic fragmentation has had little effect on the genetic characteristics of Chinese K. palmata. Rather, past decline in population size due to Late Pleistocene climate change as well as restricted pollen and seed dispersal may have contributed to low levels of both historical and contemporary gene flow, resulting in high genetic differentiation between adjacent mountain ranges due to genetic drift and inbreeding.