Burczyk Jaroslaw, Koralewski Tomasz E
Department of Genetics, Institute of Biology and Environmental Protection, University of Bydgoszcz, 85-064 Bydgoszcz, Poland.
Mol Ecol. 2005 Jul;14(8):2525-37. doi: 10.1111/j.1365-294X.2005.02593.x.
Assessment of contemporary pollen-mediated gene flow in plants is important for various aspects of plant population biology, genetic conservation and breeding. Here, through simulations we compare the two alternative approaches for measuring pollen-mediated gene flow: (i) the NEIGHBORHOOD model--a representative of parentage analyses, and (ii) the recently developed TWOGENER analysis of pollen pool structure. We investigate their properties in estimating the effective number of pollen parents (N(ep)) and the mean pollen dispersal distance (delta). We demonstrate that both methods provide very congruent estimates of N(ep) and delta, when the methods' assumptions considering the shape of pollen dispersal curve and the mating system follow those used in data simulations, although the NEIGHBORHOOD model exhibits generally lower variances of the estimates. The violations of the assumptions, especially increased selfing or long-distance pollen dispersal, affect the two methods to a different degree; however, they are still capable to provide comparable estimates of N(ep). The NEIGHBORHOOD model inherently allows to estimate both self-fertilization and outcrossing due to the long-distance pollen dispersal; however, the TWOGENER method is particularly sensitive to inflated selfing levels, which in turn may confound and suppress the effects of distant pollen movement. As a solution we demonstrate that in case of TWOGENER it is possible to extract the fraction of intraclass correlation that results from outcrossing only, which seems to be very relevant for measuring pollen-mediated gene flow. The two approaches differ in estimation precision and experimental efforts but they seem to be complementary depending on the main research focus and type of a population studied.
评估当代植物中花粉介导的基因流对于植物种群生物学、遗传保护和育种的各个方面都很重要。在这里，我们通过模拟比较了两种测量花粉介导基因流的替代方法：（i）邻域模型——亲子分析的代表，以及（ii）最近开发的花粉库结构的双基因分析。我们研究了它们在估计花粉亲本有效数量（N(ep)）和平均花粉扩散距离（δ）方面的特性。我们证明，当考虑花粉扩散曲线形状和交配系统的方法假设遵循数据模拟中使用的假设时，这两种方法对N(ep)和δ的估计非常一致，尽管邻域模型的估计方差通常较低。假设的违背，特别是自交增加或远距离花粉扩散，对这两种方法的影响程度不同；然而，它们仍然能够提供可比的N(ep)估计值。由于远距离花粉扩散，邻域模型本质上允许估计自交和异交；然而，双基因方法对自交水平的膨胀特别敏感，这反过来可能会混淆和抑制远距离花粉移动的影响。作为一种解决方案，我们证明，对于双基因方法，有可能提取仅由异交导致的组内相关性部分，这似乎与测量花粉介导的基因流非常相关。这两种方法在估计精度和实验工作量方面有所不同，但根据主要研究重点和所研究种群的类型，它们似乎是互补的。
