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

山羊胡子（婆罗门参）提供了一个独特的机会，研究基因组加倍（多倍体）后发生的遗传和基因组变化，这是一个过程，在植物中是常见的。在这一属中，有二倍体，重复形成的多倍体自然种群，形成后只有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充分的自然系统作为研究多倍体的模型。然而，Tragopogon模型的实用性受到对关系的不良理解的影响。项目目标是澄清系谱关系，包括欧亚多倍体的亲子关系;通过确定其亲子关系和在自然界中形成的频率，开发几种欧亚异源四倍体作为多倍体比较研究的额外模型;确定多倍体是否通常在一个属内的远亲物种之间而不是近亲之间形成;确定与婆罗门参属物种和物种群相关的形态特征;为正式的分类学修订奠定基础，并在网上提供正在进行的“修订”;并制定一个确定复杂群体中多倍体起源的程序。该计划是重建一个分类学上复杂的植物群的历史，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式，为未来的研究与新世界多倍体的比较。在这些最近和反复形成的异源多倍体中检测到的遗传现象的一般性可以用于解决该属中的其他多倍体。尽管杂交在婆罗门参中似乎很常见，但大多数杂交的物种都不产生异源多倍体。遗传距离和多倍体形成之间可能存在关联的假设。

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.