WSL Swiss Federal Research Institute, Zürcherstrasse 111, Birmensdorf, Switzerland.
Ann Bot. 2012 Jun;109(7):1359-67. doi: 10.1093/aob/mcs066. Epub 2012 Apr 6.
Gene flow is important in counteracting the divergence of populations but also in spreading genes among populations. However, contemporary gene flow is not well understood across alpine landscapes. The aim of this study was to estimate contemporary gene flow through pollen and to examine the realized mating system in the alpine perennial plant, Arabis alpina (Brassicaceae).
An entire sub-alpine to alpine landscape of 2 km(2) was exhaustively sampled in the Swiss Alps. Eighteen nuclear microsatellite loci were used to genotype 595 individuals and 499 offspring from 49 maternal plants. Contemporary gene flow by pollen was estimated from paternity analysis, matching the genotypes of maternal plants and offspring to the pool of likely father plants. Realized mating patterns and genetic structure were also estimated.
Paternity analysis revealed several long-distance gene flow events (≤1 km). However, most outcrossing pollen was dispersed close to the mother plants, and 84 % of all offspring were selfed. Individuals that were spatially close were more related than by chance and were also more likely to be connected by pollen dispersal.
In the alpine landscape studied, genetic structure occurred on small spatial scales as expected for alpine plants. However, gene flow also covered large distances. This makes it plausible for alpine plants to spread beneficial alleles at least via pollen across landscapes at a short time scale. Thus, gene flow potentially facilitates rapid adaptation in A. alpina likely to be required under ongoing climate change.
基因流对于抵消种群的分歧很重要，但也可以在种群之间传播基因。然而，目前人们对高山景观中的基因流还了解甚少。本研究的目的是通过花粉来估计当代基因流，并研究高山多年生植物拟南芥（十字花科）的实际交配系统。
在瑞士阿尔卑斯山，我们对 2 平方公里的亚高山到高山景观进行了全面采样。我们使用 18 个核微卫星标记对 595 个个体和 499 个来自 49 个母本植物的后代进行了基因型分析。通过亲权分析来估计花粉介导的当代基因流，将母本植物和后代的基因型与可能的父本植物库进行匹配。还估计了实际的交配模式和遗传结构。
亲权分析揭示了几个长距离基因流事件（≤1 公里）。然而，大多数异交花粉都在母株附近扩散，84%的后代都是自交的。空间上接近的个体比随机个体更相关，也更有可能通过花粉传播而连接在一起。
在研究的高山景观中，遗传结构出现在小的空间尺度上，这与高山植物的预期一致。然而，基因流也覆盖了很大的距离。这使得高山植物至少可以通过花粉在短时间内将有利等位基因传播到景观中，这是合理的。因此，基因流可能促进了拟南芥的快速适应，这在当前的气候变化下可能是必需的。
