Julian R. Starr

Plant DNA barcodes and species resolution in sedges (Carex, Cyperaceae).

We investigate the species discriminatory power of a subset of the proposed plant barcoding loci (matK, rbcL, rpoC1, rpoB, trnH‐psbA) in Carex, a cosmopolitan genus that represents one of the three largest plant genera on earth (c. 2000 species). To assess the ability of barcoding loci to resolve Carex species, we focused our sampling on three of the taxonomically best‐known groups in the genus, sections Deweyanae (6/8 species sampled), Griseae (18/21 species sampled), and Phyllostachyae (10/10 species sampled). Each group represents one of three major phylogenetic lineages previously identified in Carex and its tribe Cariceae, thus permitting us to evaluate the potential of DNA barcodes to broadly identify species across the tribe and to differentiate closely related sister species. Unlike some previous studies that have suggested that plant barcoding could achieve species identification rates around 90%, our results suggest that no single locus or multilocus barcode examined will resolve much greater than 60% of Carex species. In fact, no multilocus combination can significantly increase the resolution and statistical support (i.e., ≥ 70% bootstrap) for species than matK alone, even combinations involving the second most variable region, trnH‐psbA. Results suggest that a matK barcode could help with species discovery as 47% of Carex taxa recently named or resolved within cryptic complexes in the past 25 years also formed unique species clusters in upgma trees. Comparisons between the nrDNA internal transcribed spacer region (ITS) and matK in sect. Phyllostachyae suggest that matK not only discriminates more species (50–60% vs. 25%), but it provides more resolved phylogenies than ITS. Given the low levels of species resolution in rpoC1 and rpoB (0–13%), and difficulties with polymerase chain reaction amplification and DNA sequencing in rbcL and trnH‐psbA (alignment included), we strongly advocate that matK should be part of a universal plant barcoding system. Although identification rates in this study are low, they can be significantly improved by a regional approach to barcoding.

Polyploid and hybrid evolution in roses east of the Rocky Mountains

This study investigates the impact of hybridization and polyploidy in the evolution of eastern North American roses. We explore these processes in the Rosa carolina complex (section Cinnamomeae), which consists of five diploid and three tetraploid species. To clarify the status and origins of polyploids, a haplotype network (statistical parsimony) of the glyceraldehyde 3-phosphate dehydrogenase (GAPDH) nuclear gene was estimated for polyploids of the complex and for diploids of section Cinnamomeae in North America. A genealogical approach helped to decipher the evolutionary history of polyploids from noise created by hybridization, incomplete lineage sorting, and allelic segregation. At the diploid level, species west of the Rocky Mountains are distinct from eastern species. In the east, two groups of diploids were found: one consists of R. blanda and R. woodsii and the other of R. foliolosa, R. nitida, and R. palustris. Only eastern diploids are involved in the origins of the polyploids. Rosa arkansana is derived from the blanda-woodsii group, R. virginiana originated from the foliolosa-nitida-palustris group, and R. carolina is derived from a hybrid between the two diploid groups. The distinct origins of these polyploid taxa support the hypothesis that the three polyploids are separate species.

Potential of the 5′ and 3′ Ends of the Intergenic Spacer (IGS) of rDNA in the Cyperaceae: New Sequences for Lower‐Level Phylogenies in Sedges with an Example from Uncinia Pers.

In plants, the internal transcribed spacers (ITS; ca. 450 base pairs) of nuclear ribosomal DNA (rDNA) are the only well‐characterized nuclear sequences that are both easily amplified and appropriately variable for addressing relationships at lower taxonomic levels. In this study, we assess the utility of rDNA noncoding fragments from the external transcribed spacer 1 (ETS 1f) and from the 5′ end of the intergenic spacer ( \documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \usepackage[OT2,OT1]{fontenc} \newcommand\cyr{ \renewcommand\rmdefault{wncyr} \renewcommand\sfdefault{wncyss} \renewcommand\encodingdefault{OT2} \normalfont \selectfont} \DeclareTextFontCommand{\textcyr}{\cyr} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} \landscape

Phylogeny and Evolution in Cariceae (Cyperaceae): Current Knowledge and Future Directions

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Phylogeny of Carex subg. Vignea (Cyperaceae) Based on Non-coding nrDNA Sequence Data

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Resolving Rapid Radiations within Angiosperm Families Using Anchored Phylogenomics

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