Intra-individual polymorphism in diploid and apomictic polyploid hawkweeds (Hieracium, Lactuceae, Asteraceae): disentangling phylogenetic signal, reticulation, and noise.
Intra-individual polymorphism in diploid and apomictic polyploid hawkweeds (Hieracium, Lactuceae, Asteraceae): disentangling phylogenetic signal, reticulation, and noise.
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二倍体和副型多倍体鹰weed（Hieracium，lactuceae，astreaceae）中的个体内多态性：解开系统发育信号，网状和噪声。
DOI：
10.1186/1471-2148-9-239
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发表时间：
2009-09-22
影响因子：
3.4
通讯作者：
Chrtek J Jr
中科院分区：
文献类型：
--
作者：
Fehrer J;Krak K;Chrtek J Jr
Hieracium s.str.是一组复杂、物种丰富的多年生草本植物，由少量有性二倍体和大量无融合生殖多倍体组成。网状结构的存在和整个分类单元形态特征的近乎连续性严重影响了物种的确定，使 Hieracium 成为“植物学家的噩梦”的最佳例子之一。因此，其物种关系以前尚未通过分子方法得到解决。我们专注于假定的主要进化单位，使用核核糖体（ETS）和叶绿体（trnT-trnL）序列来理清系统发育关系并推断多倍体的起源。尽管种间变异相对较低，但核数据显示存在两个主要类群，大致对应于西欧或东欧起源的物种。广泛的网状结构主要是从亲本ETS变体的性状可加性推断出来的。令人惊讶的是，许多二倍体物种是杂交起源的，而一些多倍体类群没有显示出网状的证据。个体内的 ETS 序列多态性通常超过种间变异，并且独立于或附加于由杂交起源解释的加性模式。几种 ETS 核糖型出现在不同的混合类群中，但从未作为任何分析物种中的唯一变异。高水平的个体内 ETS 多态性阻碍了直接的系统发育分析。将这种变异表征为加性、共享信息、同质性或独特性，使得揭示系统发育信号并揭示 60 个种质中 29 个的杂交起源成为可能。与预期相反，二倍体有性生殖和多倍体无融合生殖体的分子模式没有差异。该属的基本划分为两个主要分支，此前从未在形态学上被暗示过。据认为，这两个主要群体都在不同的冰川避难所中生存下来，并由于二次接触而杂交。几条证据表明，这些数据最好的解释是存在已灭绝的变异范围和古代二倍体的更大多样性，而不是未采样的变异。人们认为灭绝的多样性和广泛的网状结构在很大程度上掩盖了物种关系。我们的研究说明了如何使用多基因序列来解开无生殖复合体或类似困难的数据集的进化历史。
Hieracium s.str. is a complex species-rich group of perennial herbs composed of few sexual diploids and numerous apomictic polyploids. The existence of reticulation and the near-continuity of morphological characters across taxa seriously affect species determination, making Hieracium one of the best examples of a 'botanist's nightmare'. Consequently, its species relationships have not previously been addressed by molecular methods. Concentrating on the supposed major evolutionary units, we used nuclear ribosomal (ETS) and chloroplast (trnT-trnL) sequences in order to disentangle the phylogenetic relationships and to infer the origins of the polyploids. Despite relatively low interspecific variation, the nuclear data revealed the existence of two major groups roughly corresponding to species with a Western or Eastern European origin. Extensive reticulation was mainly inferred from the character additivity of parental ETS variants. Surprisingly, many diploid species were of hybrid origin whilst several polyploid taxa showed no evidence of reticulation. Intra-individual ETS sequence polymorphism generally exceeded interspecific variation and was either independent of, or additional to, additive patterns accounted for by hybrid origin. Several ETS ribotypes occurred in different hybrid taxa, but never as the only variant in any species analyzed. The high level of intra-individual ETS polymorphism prevented straightforward phylogenetic analysis. Characterization of this variation as additive, shared informative, homoplasious, or unique made it possible to uncover the phylogenetic signal and to reveal the hybrid origin of 29 out of 60 accessions. Contrary to expectation, diploid sexuals and polyploid apomicts did not differ in their molecular patterns. The basic division of the genus into two major clades had not previously been intimated on morphological grounds. Both major groups are thought to have survived in different glacial refugia and to have hybridized as a result of secondary contact. Several lines of evidence suggest the data is best explained by the presence of an extinct range of variation and a larger diversity of ancestral diploids in former times rather than by unsampled variation. Extinct diversity and extensive reticulation are thought to have largely obscured the species relationships. Our study illustrates how multigene sequences can be used to disentangle the evolutionary history of agamic complexes or similarly difficult datasets.
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影响因子：
4.1
作者：
Baldwin, BG;Markos, S
通讯作者：
Markos, S
影响因子：
3.4
作者：
Göker M;Grimm GW
通讯作者：
Grimm GW
影响因子：
1.9
作者：
BALDWIN, BG;SANDERSON, MJ;DONOGHUE, MJ
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DONOGHUE, MJ
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1
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Ekenas, Catarina;Baldwin, Bruce G.;Andreasen, Katarina
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Andreasen, Katarina
影响因子：
3.6
作者：
Feliner, GN;Aguilar, JF;Rosselló, JA
通讯作者：
Rosselló, JA