Can extensive reticulation and concerted evolution result in a cladistically structured molecular data set?
Can extensive reticulation and concerted evolution result in a cladistically structured molecular data set?
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DOI：
10.1111/j.1096-0031.2001.tb00128.x
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发表时间：
2001-12-01
期刊：
影响因子：
3.6
通讯作者：
Rosselló, JA
中科院分区：
文献类型：
--
作者：
Feliner, GN;Aguilar, JF;Rosselló, JA
即使没有明确提及进化作为因果过程，层次结构也是数据集中信息量的主要标准。来自 Armeria（白花丹科）的序列数据（核核糖体 DNA ITS）包含一定量的层次结构，如数据决定性和树长度分布所示。然而，辅助证据表明，这些多拷贝区域中广泛的基因流动和有偏差的协同进化显着地塑造了 ITS 数据集。使用四个数据集的简约分析讨论了这一论点，这些数据集是通过将野生序列与来自不同代人工杂交种的序列（野生+ F-1、F-2和回交；野生+回交；野生+ F-1；野生+ F-2）组合而构建的。与F-1杂种相比，F-2在多态性位点上表现出一定程度的同质化。这种效应减少了 F-1 引起的拓扑破坏，并被认为说明了广泛的基因流和有偏差的协同进化可能如何模拟野生 ITS 数据。层次结构的出现可能是由于这两种潜在的扰动力量（或者尽管有重大贡献）而产生的，这提出了我们从这个分子数据集中恢复什么样的信号的问题。 (C) 2001 年威利亨尼格协会。
Hierarchy is the main criterion for informativeness in a data set, even if no explicit reference to evolution as a causal process is provided. Sequence data (nuclear ribosomal DNA ITS) from Armeria (Plumbaginaceae) contains a certain amount of hierarchical structure as suggested by data decisiveness and distribution of tree lengths. However, ancillary evidence suggests that extensive gene flow and biased concerted evolution in these multicopy regions have significantly shaped the ITS data set. This argument is discussed using parsimony analysis of four data sets, constructed by combining wild sequences with those from different generations of artificial hybrids (wild + F-1, F-2, and backcrosses; wild + backcrosses; wild + F-1; wild + F-2). Compared to the F-1 hybrids, F-2 show a certain degree of homogenization in polymorphic sites. This effect reduces topological disruption caused by F-1 and is considered to be illustrative of how extensive gene flow and biased concerted evolution may have modeled the wild ITS data. The possibility that hierarchy has arisen as a result of-or despite a significant contribution from-those two such potentially perturbing forces raises the question of what kind of signal are we recovering from this molecular data set. (C) 2001 The Willi Hennig Society.