Population structure affected by excess gene flow in self-pollinating Elymus nutans and E. burchan-buddae (Triticeae: Poaceae)
Population structure affected by excess gene flow in self-pollinating Elymus nutans and E. burchan-buddae (Triticeae: Poaceae)
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DOI：
10.1007/s10144-009-0169-x
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发表时间：
2009
影响因子：
1.7
通讯作者：
Xue-Bing Yan;Yuxia Guo;Fa-yang Liu;Chong Zhao;Quanlan Liu;B. Lu
中科院分区：
文献类型：
--
作者：
Xue-Bing Yan;Yuxia Guo;Fa-yang Liu;Chong Zhao;Quanlan Liu;B. Lu
种子介导的基因流可以显著影响严格自花授粉物种的种群遗传结构，但对牧区植物种群中这种基因流的程度和性质知之甚少。分子指纹图谱为解决相关问题提供了强有力的工具。利用荧光扩增片段长度多态性技术（AFLP）对青藏高原不同海拔地区的22个自花授粉牧草种群--黄背草（E. nutans）和白背草（E. burchan-buddae）的遗传结构进行了研究。分子方差分析表明，两种Elymusspecies的居群间变异分别为42.97%和37.63%，表明总变异的大部分存在于居群内。这一结果与自交植物物种的常见遗传变异模式相矛盾：群体内遗传变异较低。进一步的分析表明，在同一地区内的种群之间的基因流比不同地区之间的采样面积为两个Elymusspecies。结构分析表明，该种群具有明显的混合遗传结构，特别是同一地区相邻种群间的遗传结构，支持种群间种子扩散的假说。草原放牧动物在放牧过程中的移动促进了种子的传播，这可能是引起黄毛桉和金佛桉过度区域内基因流的原因。放牧动物传播的基因流可能会促进牧草物种遗传多样性的维持，特别是在特定区域内的小而分散的种群。
Seed-mediated gene flow can considerably affect population genetic structure of strictly self-pollinating species, but little is known on the extent and nature of such gene flow among pastoral plant populations. Molecular fingerprints provide a powerful tool to address the relevant issues. Genetic structure of 22 populations of two self-pollinating pasture species,Elymus nutansandE. burchan-buddae, collected from various altitudes of the Qinghai–Tibetan Plateau was studied using fluorescence-based amplified fragment length polymorphism technique. Analysis of molecular variance revealed 42.97% and 37.63% among-population variation for the twoElymusspecies, respectively, indicating that the majority of the total variation presented within populations. This result contradicts the common genetic variation pattern for a selfing plant species: lower genetic variation within populations. Further analysis suggested higher level of gene flow among populations within the same region than among different regions across the sampled area for the twoElymusspecies. STRUCTURE analyses of theElymuspopulations indicated an evident admixture genetic structure, particularly among neighboring populations from the same region, supporting the hypothesis of considerable seed dispersal among populations. The excess within-region gene flow ofE. nutansandE. burchan-buddaemight be caused by grazing animals that promote seed dispersal when moved around the pastoral lands during foraging. The among-population gene flow promulgated by grazing animals may promote the maintenance of genetic diversity in the pasture species, particularly in small and fragmented populations within a given region.