Systematic Studies of Tragopogon (Asteraceae): A Multi-Marker Approach to Untangling Polyploid Complexes

山羊胡子(Tragopogon)为研究基因组加倍(多倍体)后发生的遗传和基因组变化提供了一个独特的机会，这是一种在植物中常见的过程。在这个属中，有二倍体，重复形成的多倍体的自然种群，形成后仅60-80年，更古老的欧亚多倍体，人工形成的杂种和异源多倍体。因此，该属可以加入其他研究得很好的自然系统，作为研究多倍体的模式。然而，由于对关系的糟糕理解，Tragopogon模型的实用性受到了影响。项目目标是澄清欧亚多倍体的系谱关系，包括欧亚多倍体的亲缘关系；通过确定它们的亲缘关系以及它们在自然界中形成的频率，开发几个欧亚异源四倍体作为多倍体比较研究的额外模式；确定多倍体通常是在一个属内的远亲物种之间形成的，而不是近亲物种之间；确定与Tragopogon物种和物种组相关的形态特征；为正式的分类学修订奠定基础，并将正在进行的“修订”放在网上；制定一项程序，以确定复杂群体中多倍体的起源。该计划是重建分类学上复杂的植物类群的历史，澄清其分类，并为改进分类奠定基础。几个异源多倍体将被开发为新的模型，用于未来与研究得很好的新大陆多倍体的比较。在这些新近和最近形成的异源多倍体中检测到的遗传现象的共性，然后可以用来处理该属的其他多倍体。虽然杂交似乎在杂交种中很常见，但大多数杂交的物种都不会产生异源多倍体。假设遗传距离和多倍体形成之间可能存在关联。

ABSTRACTGoat's Beard (Tragopogon) provides a unique opportunity to investigate the genetic and genomic changes that occur following genome doubling (polyploidy), a process that is common in plants. In this one genus, there are diploids, natural populations of polyploids that have formed repeatedly and are only 60-80 years post-formation, older Eurasian polyploids, artificially formed hybrids and allopolyploids. As such, the genus can join other well-studied natural systems as a model for the study of polyploidy. However, the utility of the Tragopogon model is compromised by a poor understanding of relationships. Project goals are to clarify genealogical relationships, including the parentage of the Eurasian polyploids; develop several Eurasian allotetraploids as additional models for comparative studies of polyploidy by determining their parentage and how frequently they have formed in nature; determine if polyploids typically formed between distantly related species within a genus, rather than close relatives; identify morphological characters that relate species and groups of species in Tragopogon; lay the groundwork for a formal taxonomic revision and make the ongoing "revision" available on the web; and develop a process for identifying the origins of polyploids in complex groups. The plan is to reconstruct the history of a taxonomically complex group of plants, clarify its taxonomy, and lay the foundation for an improved classification. Several allopolyploids will be developed as new models for future comparisons with the well-studied New World polyploids. The generality of genetic phenomena detected in these recently and recurrently formed allopolyploids can then be used to address other polyploids in the genus. Whereas hybridization appears to be common in Tragopogon, most of those species that hybridize do not yield allopolyploids. A possible association between genetic distance and polyploid formation is hypothesized.