Diversification of the fern genus Cryptogramma across time and space

Thesis (Ph.D.) University of Alaska Fairbanks, 2016I examined diversification, biogeographic history and polyploidy within the parsley ferns (Cryptogramma) across multiple time scales. Cryptogramma is a small circumboreal genus of rock ferns in the large, diverse family Pteridaceae and is most closely related to the Asian genus Coniogramme and the monotypic Central American genus Llavea. I generated a combined six locus plastid sequence alignment (rbcL, rbcL-accD, rbcL-atpB, rps4-trnS, trnG-trnR, and trnPpetG) and a low-copy nuclear marker (gapCp) alignment for 40 accessions. Phylogenetic analysis of these datasets using maximum parsimony, maximum likelihood, and Bayesian inference demonstrate that all three genera are reciprocally monophyletic, with Cryptogramma and Coniogramme most closely related to one another. This analysis also recovered the monotypic Cryptogramma section Homopteris and sect. Cryptogramma as reciprocally monophyletic. Within sect. Cryptogramma, the unambiguously supported phylogeny supported recognizing most described species as reciprocally monophyletic clades that are mostly allopatric and can be delineated by a few morphological characters. The nuclear DNA phylogeny supported the hypothesis that the allotetraploid Cr. sitchensis originated from a hybridization event between the Asian Cr. raddeana and the Beringian Cr. acrostichoides, and the plastid DNA phylogeny revealed that Cr. acrostichoides was the maternal parent. In contrast, the tetraploid Cr. crispa appears to have originated as an autopolyploid from an undiscovered or extinct ancestor. Further phylogenetic investigation of European Cryptogramma species using DNA sequence data from 15 accessions from Europe and southwest Asia revealed that Pleistocene glacial cycles have created genetic partitioning of Cr. crispa into eastern and western clades and have also led to the formation of the Turkish auto-octoploid Cr. bithynica with Cr. crispa as the parental taxon. Divergence time estimates for key nodes were inferred using Bayesian analysis of the plastid data set coupled with secondary time constraints to reveal that crown group Cryptogramma began diversifying in the Oligocene, with most present-day species originating in the Pliocene and Pleistocene. The genus was inferred by likelihood-based ancestral area reconstruction of the chronogram and geographic distribution data to have originated in east Asia, with four colonization events reconstructed by vicariance or dispersal to the New World. My Bayesian Analysis of Macroevolutionary Mixtures (BAMM) showed no significant difference in speciation rates across time or among clades. The morphological stasis of Cryptogramma and its stable speciation rates in response to climate cycles during the Pleistocene suggest it will survive future range shifts caused by anthropogenically induced climate change.Chapter 1. Introduction -- Chapter 2. Diversification and reticulation in the circumboreal fern genus Cryptogramma -- Chapter 3. Genetic differentiation and polyploid formation within the Cryptogramma crispa complex (Polypodiales: Pteridaceae) complex -- Chapter 4. Slow and steady wins the race: the fern genus Cryptogramma survives climatic fluctuations with little apparent morphological or molecular diversification since the Oligocene -- Chapter 5. Conclusions

Future directions and priorities for Arctic bryophyte research

The development of evidence-based international strategies for the conservation and management of Arctic ecosystems in the face of climate change is hindered by critical knowledge gaps in Arctic floristic diversity and evolution. Particularly poorly studied are the bryophytes, which dominant the vegetation across vast areas of the Arctic, and consequently, play an important role in global biogeochemical cycles. Currently, much of what is known about Arctic floristic evolution is based on studies of vascular plants. Bryophytes, however, possess a number of features, such as poikilohydry, totipotency, several reproductive strategies, and the ability to disperse through microscopic diaspores, which may cause their responses to Arctic environments to differ from those of the vascular plants. Here we discuss several priority areas identified in the Arctic Council's ‘Arctic Biodiversity Assessment’ that are necessary to illuminate patterns of Arctic bryophyte evolution and diversity, including dispersal, glacial refugia, local adaptation, and ecological interactions within bryophyte-associated microbiomes. A survey of digitally available herbarium data archived in the largest online aggregate, GBIF, across the Arctic to boreal zones, indicates that sampling coverage of mosses is heterogeneous, and relatively sparse in the Arctic sensu stricostricto. A coordinated international effort across the Arctic will be necessary to address knowledge gaps in Arctic bryophyte diversity and evolution in the context of ongoing climate change

The Long Exception: Rethinking the Place of the New Deal in American History

The Long Exception examines the period from Franklin Roosevelt to the end of the twentieth century and argues that the New Deal was more of an historical aberration—a byproduct of the massive crisis of the Great Depression—than the linear triumph of the welfare state. The depth of the Depression undoubtedly forced the realignment of American politics and class relations for decades, but, it is argued, there is more continuity in American politics between the periods before the New Deal order and those after its decline than there is between the postwar era and the rest of American history. Indeed, by the early seventies the arc of American history had fallen back upon itself. While liberals of the seventies and eighties waited for a return to what they regarded as the normality of the New Deal order, they were actually living in the final days of what Paul Krugman later called the interregnum between Gilded Ages. The article examines four central themes in building this argument: race, religion, class, and individualism

Polyploidy in gymnosperms – Insights into the genomic and evolutionary consequences of polyploidy in Ephedra

While polyploidization is recognized as a major evolutionary driver for ferns and angiosperms, little is known about its impact in gymnosperms, where polyploidy is much less frequent. We explore Ephedra to evaluate (i) the extent of genome size diversity in the genus and the influence polyploidy has had on the evolution of nuclear DNA contents, and (ii) identify where shifts in genome size and polyploidy have occurred both temporally and spatially. A phylogenetic framework of all Ephedra species together with genome sizes and karyotypes for 87% and 67% of them respectively, were used to explore ploidy evolution and its global distribution patterns. Polyploidy was shown to be extremely common, with 41 species (83%) being polyploid (up to 8×) or having polyploid cytotypes – the highest frequency and level reported for any gymnosperm. Genome size was also diverse, with values ranging ~5-fold (8.09–38.34 pg/1C) – the largest range for any gymnosperm family – and increasing in proportion to ploidy level (i.e. no genome downsizing). Our findings provide novel data which support the view that gymnosperms have a more conserved mode of genomic evolution compared with angiosperms.The work was partially supported by a DAAD Research Fellowship to SIB for a research stay in the Renner Lab at LMU, Munich, Germany. OH and JP benefited from Ramón y Cajal fellowships (RYC-2016-21176 and RYC-2017-22742, respectively).Highlights Abstract Graphical abstract Keywords 1. Introduction 2. Materials and methods 3. Results 4. Discussion Author contributions Declaration of Competing Interest Acknowledgements Appendix A. Supplementary material Reference

Relation between stable isotope ratios in human red blood cells and hair: implications for using the nitrogen isotope ratio of hair as a biomarker of eicosapentaenoic acid and docosahexaenoic acid1234

Background: The nitrogen isotope ratio (expressed as δ15N) of red blood cells (RBCs) is highly correlated with the RBC long-chain ω−3 (n−3) fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in Yup'ik Eskimos. Because δ15N can also be measured in hair samples, it could provide a noninvasive, retrospective biomarker for EPA and DHA intakes