Taxon sampling and seed plant phylogeny
Taxon sampling and seed plant phylogeny
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DOI：
10.1111/j.1096-0031.2002.tb00288.x
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发表时间：
2002-10-01
期刊：
影响因子：
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通讯作者：
Källersjö, M
中科院分区：
文献类型：
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作者：
Rydin, C;Källersjö, M
我们通过交换种子植物的两种大小的 rbcL 矩阵中的末端，对 10 个 38 分类单元矩阵和 10 个 80 分类单元矩阵应用简约性和贝叶斯分析，研究了分类单元采样对系统发育推断的影响。在比较树的拓扑结构时，我们关注了买麻藤目的位置，这是一个重要的类群，其位置长期以来一直存在争议。无论采用哪种方法，从不同分类单元样本中获得的树木都可能相互矛盾，甚至在似乎得到强烈支持的群体上存在分歧。添加终端提高了未加权简约性结果的一致性，但对于排除第三位置的简约性和贝叶斯分析没有改善，特别是在采用一般时间可逆模型时。这表明，尝试仅使用几个分类单元来解决深层关系可能会导致虚假结论，分组不太可能用不同的分类单元样本或更大的数据集重复。分类单元取样的效果尚未得到普遍认识，种子植物的系统发育研究通常基于少数分类单元。这种不充分的采样可能有助于解释近年来提出的种子植物的各种系统发育假说。我们建议应使用终端的替代选择来重新分析受限数据集（例如多基因研究的单基因子集）以评估拓扑一致性。 (C) 2002 年爱思唯尔科学（美国）。版权所有。
We investigated the effects of taxon sampling on phylogenetic inference by exchanging terminals in two sizes of rbcL matrices for seed plants, applying parsimony and bayesian analyses to ten 38-taxon matrices and ten 80-taxon matrices. In comparing tree topologies we concentrated on the position of the Gnetales, an important group whose placement has long been disputed. With either method, trees obtained from different taxon samples could be mutually contradictory and even disagree on groups that seemed strongly supported. Adding terminals improved the consistency of results for unweighted parsimony, but not for parsimony with third positions excluded and not for bayesian analysis, particularly when the general time-reversible model was employed. This suggests that attempting to resolve deep relationships using only a few taxa can lead to spurious conclusions, groupings unlikely to be repeatable with different taxon samplings or larger data sets. The effect of taxon sampling has not generally been recognized, and phylogenetic studies of seed plants have often been based on few taxa. Such insufficient sampling may help explain the variety of phylogenetic hypotheses for seed plants proposed in recent years. We recommend that restricted data sets such as single-gene subsets of multigene studies should be reanalyzed with alternative selections of terminals to assess topological consistency. (C) 2002 Elsevier Science (USA). All rights reserved.