Phylogenetic, morphological, and chemotaxonomic incongruence in the North American endemic genus Echinacea
Phylogenetic, morphological, and chemotaxonomic incongruence in the North American endemic genus Echinacea
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DOI：
10.3732/ajb.0800049
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发表时间：
2008-06-01
影响因子：
3
通讯作者：
Wendel, Jonathan F.
中科院分区：
文献类型：
--
作者：
Flagel, Lex E.;Rapp, Ryan A.;Wendel, Jonathan F.
对新近形成的物种的研究很重要，因为它可以帮助我们更好地理解生物的分化和物种形成过程。然而，这些物种经常在分子系统发育领域提出困难的挑战，因为驱动分子分歧的过程可能落后于表型分歧。在目前的研究中，我们表明最近分化的北美特有的紫色锥花属松果菊的物种具有较低的分子分歧水平。来自三个核基因座和两个叶绿体基因座的数据既没有提供已解决的拓扑结构，也没有关于物种水平关系的一致假设。这种缺乏系统发育的分辨率可能是由于不完全的谱系分类、杂交和二次接触后的回交所致。分子标记提供的低分辨率与之前的研究形成了对比，这些研究从代谢和形态数据中发现了良好的分辨率和分类学支持的关系。这些结果表明，表型管化，导致可识别的形态物种，在紫锥菊中发生得很快。相反，分子信号被基因流动和不完全的谱系分类所扭曲。在这里，我们探索自然历史对紫锥菊的遗传组织和系统发育关系的影响。
The study of recently formed species is important because it can help us to better understand organismal divergence and the speciation process. However, these species often present difficult challenges in the field of molecular phylogenetics because the processes that drive molecular divergence can lag behind phenotypic divergence. In the current study we show that species of the recently diverged North American endemic genus of purple coneflower, Echinacea, have low levels of molecular divergence. Data from three nuclear loci and two plastid loci provide neither resolved topologies nor congruent hypotheses about species-level relationships. This lack of phylogenetic resolution is likely due to the combined effects of incomplete lineage sorting, hybridization, and backcrossing following secondary contact. The poor resolution provided by molecular markers contrasts previous studies that found well-resolved and taxonomically supported relationships from metabolic and morphological data. These results suggest that phenotypic canalization, resulting in identifiable morphological species, has occurred rapidly within Echinacea. Conversely, molecular signals have been distorted by gene flow and incomplete lineage sorting. Here we explore the impact of natural history on the genetic organization and phylogenetic relationships of Echinacea.