Maia Leonardo P, Colato Alexandre, Fontanari José F
Instituto de Física de São Carlos, Universidade de São Paulo, Caixa Postal 369, São Carlos, SP 13560-970, Brazil.
J Theor Biol. 2004 Feb 7;226(3):315-20. doi: 10.1016/j.jtbi.2003.09.005.
Selection is one of the factors that most influence the shape of genealogical trees. Here we report results of simulations of the infinite-sites version of Moran's model of population genetics aiming at quantifying how the presence of selection affects the branching pattern (topology) of binary genealogical trees. In particular, we consider a scenario of purifying or negative selection in which all mutations are deleterious and each new mutation reduces the fitness of the individual by the same fraction. Analysis of five statistical measures of tree balance or symmetry borrowed from taxonomy indicates that the genealogical trees of samples of populations in which selection is actuating are in the average more asymmetric than neutral trees and that this effect is enhanced by increasing the sample size. However, a quantitative evaluation of the power of these balance measures to detect a tree topology significantly distinct from the neutral one indicates that they are not useful as tests of neutrality of mutations.
选择是对系谱树形状影响最大的因素之一。在此，我们报告了群体遗传学中莫兰模型无限位点版本的模拟结果，旨在量化选择的存在如何影响二叉系谱树的分支模式（拓扑结构）。具体而言，我们考虑一种纯化或负选择的情况，即所有突变都是有害的，且每个新突变都会使个体的适应度降低相同比例。从分类学借用的五种树平衡或对称性统计量度分析表明，正在发生选择的群体样本的系谱树平均而言比中性树更不对称，并且这种效应会随着样本量的增加而增强。然而，对这些平衡量度检测与中性拓扑结构显著不同的树拓扑结构的能力进行的定量评估表明，它们作为突变中性的检验并无用处。
