Spatial genetic structure in continuous and fragmented populations of Pinus pinaster Aiton
Spatial genetic structure in continuous and fragmented populations of Pinus pinaster Aiton
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DOI：
10.1111/j.1365-294x.2009.04372.x
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发表时间：
2009-11-01
影响因子：
4.9
通讯作者：
Heuertz, M.
中科院分区：
文献类型：
--
作者：
De-Lucas, A. I.;Gonzalez-Martinez, S. C.;Heuertz, M.
生境破碎化，即，种群减少成小的孤立的残余物，预计将增加空间遗传结构（SGS）的植物种群通过非随机交配，较低的种群密度和潜在的生殖个体的聚集。采用实验和模拟相结合的方法，研究了种群规模缩小和遗传隔离对海岸松（Pinus pinaster艾顿）SGS的影响。海岸松是一种风媒传粉的针叶树，由于森林火灾和栖息地破碎化，其在伊比利亚半岛的分布较为分散。从伊比利亚半岛的两个人口对，形成了一个连续的和一个分散的人口，共394个人的5个高度多态性的核微卫星基因型。与预测一致，SGS是显着的，更强的片段（Sp = 0.020和Sp = 0.026）比连续的人口，其中显着的SGS检测到一个人口（Sp = 0.010）。模拟结果表明，在厚尾扩散下，小种群规模比遗传隔离对SGS的影响更大，而在正常扩散下，遗传隔离对SGS的影响更大。SGS总是强于在真实的人口比在模拟，除非不切实际的窄扩散和/或高方差的繁殖成功的建模（即使占潜在的高估SGS在真实的人口作为一个结果，短距离采样）。这表明，在模拟中没有考虑的因素，如非随机交配或选择，另外在伊比利亚海岸松种群的SGS操作。
Habitat fragmentation, i.e., the reduction of populations into small isolated remnants, is expected to increase spatial genetic structure (SGS) in plant populations through nonrandom mating, lower population densities and potential aggregation of reproductive individuals. We investigated the effects of population size reduction and genetic isolation on SGS in maritime pine (Pinus pinaster Aiton) using a combined experimental and simulation approach. Maritime pine is a wind-pollinated conifer which has a scattered distribution in the Iberian Peninsula as a result of forest fires and habitat fragmentation. Five highly polymorphic nuclear microsatellites were genotyped in a total of 394 individuals from two population pairs from the Iberian Peninsula, formed by one continuous and one fragmented population each. In agreement with predictions, SGS was significant and stronger in fragments (Sp = 0.020 and Sp = 0.026) than in continuous populations, where significant SGS was detected for one population only (Sp = 0.010). Simulations suggested that under fat-tailed dispersal, small population size is a stronger determinant of SGS than genetic isolation, while under normal dispersal, genetic isolation has a stronger effect. SGS was always stronger in real populations than in simulations, except if unrealistically narrow dispersal and/or high variance of reproductive success were modelled (even when accounting for potential overestimation of SGS in real populations as a result of short-distance sampling). This suggests that factors such as nonrandom mating or selection not considered in the simulations were additionally operating on SGS in Iberian maritime pine populations.