Polyploidy (the multiplication of chromosome sets within a nucleus) and apomixis (the production of embryos without fertilization) are encountered in many living organisms. Their roles in the propagation of hybrids (in wheat, cotton, citrus, etc.) are well documented, but their effects on genetic diversity and geographic distribution are largely unexplored. Polyploidy and apomixis are especially prevalent in cheilanthoid ferns, a group of 500+ species adapted to seasonally dry habitats avoided by most other ferns, and they clearly have contributed to the ability of these species to prosper in these climatically-challenged environments. Using a combination of genetic (DNA, protein, and chromosome) and morphological analyses, this project will explore this apparent connection between polyploidy and apomixis, genetic diversity, and the ability to colonize marginal habitats.
This study will examine how polyploidy and apomixis have contributed to the evolutionary success of xeric-adapted plants, facilitating the development of hypotheses applicable to land plants in general. Such studies may prove critical in the face of global climate change and increasing aridity. Additional goals include development of an online identification guide, creation of teaching modules for use by high school teachers, graduate and postgraduate training in systematics, and outreach to students and professionals in countries hosting field work.
Participants 3 senior personnel: Kathleen Pryer (PI), Michael Windham (co-PI), Layne Huiet 2 postdocs: James Beck, Eric Schuettpelz 4 graduate students: Amanda Grusz, Carl Rothfels, Erin Sigel, Fay-Wei Li 1 undergraduate student: Anne Johnson Organizational Partners Organization for Tropical Studies: This partnership allowed the PIs to fulfill a major outreach educational component of this grant. From Jan 8-24, 2008, the two PIs were full-time invited faculty members for the Specialty course 'Tropical Ferns and Lycophytes' that was offered by OTS (for only the second time in 40 years!). Our three graduate students (Carl Rothfels, Amanda Grusz, and Erin Sigel) all participated in this landmark course. Activities and Findings 1. Using three plastid markers (rbcL, atpA, trnG-trnR), a robust phylogenetic framework was established for a sampling of 250 cheilanthoid ferns (about 60% of the recognized species diversity). This has led to the recognition of numerous well-supported monophyletic groups that provide a solid foundation for redefining genera. 2. Cheilanthoid generic case studies were carried out that teased apart diploids vs. polyploids, sexual taxa vs. apomictics, and narrowly endemic vs. widespread taxa across cheilanthoids. These studies represent major advances in our understanding of evolutionary patterns and species diversity in Cheilanthes, Notholaena, Astrolepis, Pentagrama, Argyrochosma, as well as naming the new genus, Gaga. An additional six manuscrripts are in various stages of preparation; when published, these will complete the partitioning of cheilanthoid biodiversity into definable, monophyletic genera. Training and Development: A total of six postdocs and graduate students (two women, four men) and one female undergraduate participated in this grant and received interdisciplinary training in fern systematics, fern biology, and phylogenetic/comparative methods -- all of which are essential to the development of the next generation of systematists and evolutionary biologists and to their ability to carry out innovative research and ask important questions about plant evolution. Outreach Activities: The most prominent of our outreach activities was: One of our publications was listed among Duke's Top Ten Stories of 2012: Li, F.-W., K.M. Pryer, and M.D. Windham. 2012. Gaga, a new fern genus segregated from Cheilanthes (Pteridaceae). Systematic Botany 37: 845-860. In late October 2012, we published a paper that named a new genus of 19 ferns in honor of mega-pop star Lady Gaga, in recognition of her human rights activism that led to the Born This Way Foundation. There has been an overwhelmingly positive response to our publication from all corners of the globe, such that six weeks later, a Google Search for 'gaga fern' lists more than 10,000 results ranging from print (e.g., New York Times, Ottawa Citizen, Duke Chronicle,...), radio (WUNC Morning edition, ..), and internet media (e.g. National Geographic, NSF, Rolling Stone, MTV, Huffington Post...), including blogs, twitter and facebook posts, etc. Duke's YouTube video, which explains the science and art connection behind the story, has had more than 46,000 views. Overall, a positive outreach move: a lot of people who did not know the words 'herbarium' or 'genus' or 'fern', know them now...! According to Huffington Post, our paper was the most popular Botany story for 2012.www.huffingtonpost.com/dr-chris-martine/top-new-plant-species-of-last-year_b_2473154.html Publications and Presentations: To date, a total of 19 refereed papers have been published (15 are in print and 4 are still in review). We estimate that another six papers (at least) are still in the pipeline and will be published within the next couple of years. A total of 20 oral presentations were given at national and international botanical meetings. Web/Internet Products URL(s): www.fernlab.biology.duke.edu http://tolweb.org/Pteridaceae/29352
