Simmons Mark P, Zhang Li-Bing, Webb Colleen T, Müller Kai
Department of Biology, Colorado State University, Fort Collins, CO 80523, USA.
Mol Phylogenet Evol. 2007 Feb;42(2):528-42. doi: 10.1016/j.ympev.2006.08.008. Epub 2006 Aug 22.
AFLPs (and to a lesser extent ISSRs and RAPDs) are increasingly being used for phylogenetic inference among closely related species. Presence/absence characters for each AFLP allele treat all absences as homologous to one another. With three or more alleles, terminals are grouped by their shared absence of alleles in character-based phylogenetic-inference methods in a manner that is not redundant with their shared presence of an alternative allele. We conducted simulations to quantify how severe the negative effect of using presence/absence characters of individual bands is for phylogenetic inference relative to standard multistate characters. We examined alternative tree topologies, relative branch lengths, numbers of characters, rates of evolution, and numbers of alternative alleles, using both parsimony and Nei-and-Li distance analyses. Multistate parsimony generally outperformed presence/absence parsimony, which in turn outperformed Nei-and-Li distance. Increasing the character-state space (i.e., the number of alternative character states available) was found to be advantageous for all three methods of analysis examined, but was most advantageous for multistate parsimony. However, the advantage of multistate parsimony relative to Nei-and-Li distance decreased when applied to more divergent characters. More parsimony-informative variation generally alleviated the problem associated with scoring multistate characters as presence/absence characters. The ensemble consistency index was lower for presence/absence characters relative to multistate characters.
扩增片段长度多态性(以及程度稍低的简单序列重复区间和随机扩增多态性DNA)越来越多地用于密切相关物种间的系统发育推断。每个扩增片段长度多态性等位基因的存在/缺失特征将所有缺失视为彼此同源。对于三个或更多等位基因,在基于特征的系统发育推断方法中,分类群根据其共享的等位基因缺失进行分组,这种方式与其共享的另一个等位基因的存在并不冗余。我们进行了模拟,以量化相对于标准多态性状,使用单个条带的存在/缺失特征对系统发育推断的负面影响有多严重。我们使用简约法和内氏距离分析,研究了不同的树形拓扑结构、相对分支长度、特征数量、进化速率和替代等位基因数量。多态简约法通常优于存在/缺失简约法,而存在/缺失简约法又优于内氏距离法。发现增加特征状态空间(即可用的替代特征状态数量)对所研究的所有三种分析方法都有利,但对多态简约法最为有利。然而,当应用于差异更大的特征时,多态简约法相对于内氏距离法的优势会降低。更多的简约信息变异通常缓解了将多态性状计分为存在/缺失性状所带来的问题。相对于多态性状,存在/缺失性状的总体一致性指数更低。