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

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

A community-derived classification for extant lycophytes and ferns

Phylogeny has long informed pteridophyte classification. As our ability to infer evolutionary trees has improved, classifications aimed at recognizing natural groups have become increasingly predictive and stable. Here, we provide a modern, comprehensive classification for lycophytes and ferns, down to the genus level, utilizing a community-based approach. We use monophyly as the primary criterion for the recognition of taxa, but also aim to preserve existing taxa and circumscriptions that are both widely accepted and consistent with our understanding of pteridophyte phylogeny. In total, this classification treats an estimated 11 916 species in 337 genera, 51 families, 14 orders, and two classes. This classification is not intended as the final word on lycophyte and fern taxonomy, but rather a summary statement of current hypotheses, derived from the best available data and shaped by those most familiar with the plants in question. We hope that it will serve as a resource for those wanting references to the recent literature on pteridophyte phylogeny and classification, a framework for guiding future investigations, and a stimulus to further discourse

A Toolbox for Triticeae Genomics

International audienceIn the last two decades, progress in cereal genomics has been remarkable, enabling a better understanding of the structure and function of the cereal genomes. However, significant advances mainly concerned rice and maize, whereas for the Triticeae species, namely wheat, barley and rye, the development of genomic tools and resources has long been hampered by the size and the complexity of their genomes. Recently, new technologies have allowed the development of a toolbox for Triticeae genomics comparable to what is available for rice and maize. Triticeae scientists and breeders can now benefit from a wide range of tools, including molecular markers, genetic maps, EST sequences, microrarrays, BAC libraries and transformation systems that can be applied to structural, functional, evolutionary and comparative genomic studies of the Triticeae genomes