Goat'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.
