Browsing by Author "Grusz, AL"
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Item Open Access Deciphering the origins of apomictic polyploids in the Cheilanthes yavapensis complex (Pteridaceae).(American journal of botany, 2009-09) Grusz, AL; Windham, MD; Pryer, KMDeciphering species relationships and hybrid origins in polyploid agamic species complexes is notoriously difficult. In this study of cheilanthoid ferns, we demonstrate increased resolving power for clarifying the origins of polyploid lineages by integrating evidence from a diverse selection of biosystematic methods. The prevalence of polyploidy, hybridization, and apomixis in ferns suggests that these processes play a significant role in their evolution and diversification. Using a combination of systematic approaches, we investigated the origins of apomictic polyploids belonging to the Cheilanthes yavapensis complex. Spore studies allowed us to assess ploidy levels; plastid and nuclear DNA sequencing revealed evolutionary relationships and confirmed the putative progenitors (both maternal and paternal) of taxa of hybrid origin; enzyme electrophoretic evidence provided information on genome dosage in allopolyploids. We find here that the widespread apomictic triploid, Cheilanthes lindheimeri, is an autopolyploid derived from a rare, previously undetected sexual diploid. The apomictic triploid Cheilanthes wootonii is shown to be an interspecific hybrid between C. fendleri and C. lindheimeri, whereas the apomictic tetraploid C. yavapensis is comprised of two cryptic and geographically distinct lineages. We show that earlier morphology-based hypotheses of species relationships, while not altogether incorrect, only partially explain the complicated evolutionary history of these ferns.Item Open Access Development of microsatellite markers for the apomictic triploid fern Myriopteris lindheimeri (Pteridaceae).(Applications in plant sciences, 2015-11-10) Grusz, AL; Pryer, KMPREMISE OF THE STUDY:Microsatellite markers were developed for investigating the population dynamics of Myriopteris lindheimeri (Pteridaceae), an apomictic triploid fern endemic to deserts of the southwestern United States and Mexico. METHODS AND RESULTS:Using 454 sequencing, 21 microsatellite markers were developed. Of these, 14 were polymorphic with up to five alleles per locus and eight markers amplified in one or more congeneric close relatives (M. covillei, M. fendleri, M. aurea, and M. rufa). To demonstrate marker utility, M. lindheimeri samples from three Arizona populations were genotyped at nine loci. For each population, diversity measures including percent polymorphic loci, frequency of heterozygotes across all loci, and genotypic diversity were calculated. Across the three populations, on average, 63% of loci were polymorphic, the average frequency of heterozygotes (across all loci) was 0.32, and average genotypic diversity was 0.34. CONCLUSIONS:These markers provide a foundation for future studies exploring polyploidy and apomixis in myriopterid ferns.Item Open Access Patterns of diversification in the xeric-adapted fern genus myriopteris (Pteridaceae)(Systematic Botany, 2014-01-01) Grusz, AL; Windham, MD; Yatskievych, G; Huiet, L; Gastony, GJ; Pryer, KMStrong selective pressures imposed by drought-prone habitats have contributed to extensive morphological convergence among the 400 + species of cheilanthoid ferns (Pteridaceae). As a result, generic circumscriptions based exclusively on macromorphology often prove to be non-monophyletic. Ongoing molecular phylogenetic analyses are providing the foundation for a revised classification of this challenging group and have begun to clarify its complex evolutionary history. As part of this effort, we generated and analyzed DNA sequence data for three plastid loci (rbcL, atpA, and the intergenic spacer trnG-trnR) for the myriopterid clade, one of the largest monophyletic groups of cheilanthoid ferns. This lineage encompasses 47 primarily North and Central American taxa previously included in Cheilanthes but now placed in the recircumscribed genus Myriopteris. Here, we infer a phylogeny for the group and examine key morphological characters across this phylogeny. We also include a brief discussion of the three well-supported Myriopteris subclades, along with a review of reproductive mode and known ploidy levels for members of this early diverging lineage of cheilanthoid ferns. © Copyright 2014 by the American Society of Plant Taxonomists.Item Open Access Refining the phylogeny of cheilanthoid ferns: The resurrection and recircumscription of Myriopteris (Pteridaceae)(Systematic Botany, 2013) Grusz, AL; Pryer, KM; Yatskievych, G; Huiet, RL; Gastony, GJ; Windham, MDItem Open Access The evolution of chloroplast genes and genomes in ferns.(Plant molecular biology, 2011-07) Wolf, PG; Der, JP; Duffy, AM; Davidson, JB; Grusz, AL; Pryer, KMMost of the publicly available data on chloroplast (plastid) genes and genomes come from seed plants, with relatively little information from their sister group, the ferns. Here we describe several broad evolutionary patterns and processes in fern plastid genomes (plastomes), and we include some new plastome sequence data. We review what we know about the evolutionary history of plastome structure across the fern phylogeny and we compare plastome organization and patterns of evolution in ferns to those in seed plants. A large clade of ferns is characterized by a plastome that has been reorganized with respect to the ancestral gene order (a similar order that is ancestral in seed plants). We review the sequence of inversions that gave rise to this organization. We also explore global nucleotide substitution patterns in ferns versus those found in seed plants across plastid genes, and we review the high levels of RNA editing observed in fern plastomes.Item Open Access The utility of nuclear gapCp in resolving polyploid fern origins(Systematic Botany, 2008-10-01) Schuettpelz, E; Grusz, AL; Windham, MD; Pryer, KMAlthough polyploidy is rampant in ferns and plays a major role in shaping their diversity, the evolutionary history of many polyploid species remains poorly understood. Nuclear DNA sequences can provide valuable information for identifying polyploid origins; however, remarkably few nuclear markers have been developed specifically for ferns, and previously published primer sets do not work well in many fern lineages. In this study, we present new primer sequences for the amplification of a portion of the nuclear gapCp gene (encoding a glyceraldehyde-3-phosphate dehydrogenase). Through a broad survey across ferns, we demonstrate that these primers are nearly universal for this clade. With a case study in cheilanthoids, we show that this rapidly evolving marker is a powerful tool for discriminating between autopolyploids and allopolyploids. Our results indicate that gapCp holds considerable potential for addressing species-level questions across the fern tree of life. © Copyright 2008 by the American Society of Plant Taxonomists.Item Open Access Toward a monophyletic Notholaena (Pteridaceae): Resolving patterns of evolutionary convergence in xeric-adapted ferns(Taxon, 2008-01-01) Rothfels, CJ; Windham, MD; Grusz, AL; Gastony, GJ; Pryer, KMCheilanthoid ferns (Pteridaceae) are a diverse and ecologically important clade, unusual among ferns for their ability to colonize and diversify within xeric habitats. These extreme habitats are thought to drive the extensive evolutionary convergence, and thus morphological homoplasy, that has long thwarted a natural classification of cheilanthoid ferns. Here we present the first multigene phylogeny to focus on taxa traditionally assigned to the large genus Notholaena. New World taxa (Notholaena sensu Tryon) are only distantly related to species occurring in the Old World (Notholaena sensu Pichi Sermolli). The circumscription of Notholaena adopted in recent American floras is shown to be paraphyletic, with species usually assigned to Cheilanthes and Cheiloplecton nested within it. The position of Cheiloplecton is particularly surprising - given its well-developed false indusium and non-farinose blade, it is morphologically anomalous within the "notholaenoids". In addition to clarifying natural relationships, the phylogenetic hypothesis presented here helps to resolve outstanding nomenclatural issues and provides a basis for examining character evolution within this diverse, desert-adapted clade.Item Open Access Using Plastid and Nuclear DNA Sequences to Redraw Generic Boundaries and Demystif Species Complexes in Cheilanthoid Ferns.(AMERICAN FERN JOURNAL, 2009-04-01) Windham, MD; Huiet, L; Schuettpelz, E; Grusz, AL; Rothfels, C; Beck, J; Yatskievych, G; Pryer, KM