Polyploid genomes in the earliest stages of evolution (as in Tragopogon) are precisely the tool needed to better understand the connection between early events of duplicate gene evolution and the longer-term trajectory of genome evolution following polyploidy (whole-genome duplication). Furthermore, repeated origins of the same polyploids in a small geographic area and narrow time frame provide the unique opportunity to ask if evolution repeats itself across independently formed lineages. Tragopogon represents in microcosm what occurs in other polyploids over much larger geographic areas and longer time frames; it is an important, multifaceted, evolutionary and now genetic model system. With OPUS support from NSF, we propose to synthesize our vast data for the unique system provided by both new and older polyploids in Tragopogon. This synthesis will not only provide novel insights, but also set the stage for future work by researchers in diverse areas to investigate the ecology, patterns, tempo, mechanisms, and evolutionary forces driving post-WGD genome evolution.
Some of us have studied Tragopogon for over 36 years, beginning in 1984, after moving to Washington State University (first publications: Soltis and Soltis 1989; 1991). Pullman is one of the first sites of formation for the tetraploids (Ownbey 1950). Others in our group have been investigating the system for 20 years. We were astounded by how common the polyploids had become in the several decades since Ownbey (1950) first described the populations of the newly formed allotetraploids (<100 individuals) as “small and precarious”; noting that they had “attained a degree of success” and appeared to be “competing successfully” with their diploid parents. He added that it would be “important to follow the … newly formed polyploids through time.”
We have had the opportunity to investigate the Tragopogon system in the field and lab using a large array of molecular methods, cytogenetic approaches, as well as morphological and garden garden analyses. We have examined the number of origins of the polyploids, genetic variation within and among populations, as well as the mating systems of the diploid progenitors and polyploids. We used the repeated formations of the polyploids to ask – does evolution repeat itself across independent formations of the same polyploid species? How much of evolution is hard wired (predictable) vs stochastic? Our amazing team has published over 70 papers on Tragopogon. We summarize much of that collaborative work on this website. Many of our team owe much of his/her careers to two newly formed polyploids and the research opportunities they provided, supported in large part via NSF.
After three decades of work, we feel it is time for “global synthesis” of the multiple, disparate datasets we have available for Tragopogon (some data still require adequate compilation), including new analyses of existing data to address fundamental new questions. It is also important to make all of our resources readily available to others–setting the stage for the next generation of study on this model system by other researchers. The system also affords exciting opportunities for novel outreach in that Tragopogon represents speciation before your eyes. With OPUS support we will synthesize and reanalyze our existing data as follows: 1) Natural populations—compile exact locations for future workers; 2) Introductions from Europe and genotypes now in US; 3) Crossing studies; 4) Multi-omics integrative analysis (Transcriptomes; Reference genomes; Proteome data; Alternative Splicing); 5) Synthetic lines; 6) Ecological data (greenhouse data; Niche modeling); In section 3 we cover: 7) Outreach (Short film); 8) Website (Background; Resources; Methods; Seed Stocks; Genome resources).
We seek to address key questions that will promote novel understanding of polyploidy. We will provide new insights into recurring formation and the consequences of genomic merger. For example, Tragopogon polyploids have formed multiple times – although there are many parental dipoid genotypes, are only a few combinations actually involved in polyploidization? With an increased arsenal of genomic tools – what are the genetic and proteomic consequences of recent genome doubling? Are there rules? Are there immediate changes in alternative splicing? Does the proteome reflect the transcriptome? Are immediate changes a good predictor of what occurs deeper in time?
Collecting Tragopogon mirus in 1998. Plants are in fruit. This is the Palouse, WA location, one of the locations reported early on by Marion Ownbey.