Burczyk J, Adams W T, Birkes D S, Chybicki I J
Department of Genetics, Insitute of Biology and Environmental Protection, University of Bydgoszcz, Poland.
Genetics. 2006 May;173(1):363-72. doi: 10.1534/genetics.105.046805. Epub 2006 Feb 19.
Estimating seed and pollen gene flow in plants on the basis of samples of naturally regenerated seedlings can provide much needed information about "realized gene flow," but seems to be one of the greatest challenges in plant population biology. Traditional parentage methods, because of their inability to discriminate between male and female parentage of seedlings, unless supported by uniparentally inherited markers, are not capable of precisely describing seed and pollen aspects of gene flow realized in seedlings. Here, we describe a maximum-likelihood method for modeling female and male parentage in a local plant population on the basis of genotypic data from naturally established seedlings and when the location and genotypes of all potential parents within the population are known. The method models female and male reproductive success of individuals as a function of factors likely to influence reproductive success (e.g., distance of seed dispersal, distance between mates, and relative fecundity--i.e., female and male selection gradients). The method is designed to account for levels of seed and pollen gene flow into the local population from unsampled adults; therefore, it is well suited to isolated, but also wide-spread natural populations, where extensive seed and pollen dispersal complicates traditional parentage analyses. Computer simulations were performed to evaluate the utility and robustness of the model and estimation procedure and to assess how the exclusion power of genetic markers (isozymes or microsatellites) affects the accuracy of the parameter estimation. In addition, the method was applied to genotypic data collected in Scots pine (isozymes) and oak (microsatellites) populations to obtain preliminary estimates of long-distance seed and pollen gene flow and the patterns of local seed and pollen dispersal in these species.
基于自然再生幼苗样本估计植物中的种子和花粉基因流，可以提供有关“实际基因流”的急需信息，但这似乎是植物种群生物学中最大的挑战之一。传统的亲子关系方法，由于其无法区分幼苗的父本和母本，除非有单亲遗传标记的支持，否则无法精确描述幼苗中实现的基因流的种子和花粉方面。在这里，我们描述了一种最大似然方法，用于根据自然建立的幼苗的基因型数据以及种群中所有潜在亲本的位置和基因型已知时，对本地植物种群中的母本和父本进行建模。该方法将个体的雌性和雄性繁殖成功率建模为可能影响繁殖成功率的因素（例如种子传播距离、配偶之间的距离以及相对繁殖力——即雌性和雄性选择梯度）的函数。该方法旨在考虑未采样成年个体流入本地种群的种子和花粉基因流水平；因此，它非常适合孤立的，但也广泛分布的自然种群，在这些种群中，广泛的种子和花粉传播使传统的亲子关系分析变得复杂。进行了计算机模拟，以评估模型和估计程序的实用性和稳健性，并评估遗传标记（同工酶或微卫星）的排除能力如何影响参数估计的准确性。此外，该方法应用于在苏格兰松（同工酶）和橡树（微卫星）种群中收集的基因型数据，以获得这些物种中长距离种子和花粉基因流以及本地种子和花粉传播模式的初步估计。
