Publications by authors named "David Wickell"

Premise: There is a general lack of consensus on the best practices for filtering of single-nucleotide polymorphisms (SNPs) and whether it is better to use SNPs or include flanking regions (full "locus") in phylogenomic analyses and subsequent comparative methods.

Methods: Using genotyping-by-sequencing data from 22 species, we assessed the effects of SNP vs. locus usage and SNP retention stringency.

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Homosporous lycophytes (Lycopodiaceae) are a deeply diverged lineage in the plant tree of life, having split from heterosporous lycophytes ( and ) ~400 Mya. Compared to the heterosporous lineage, Lycopodiaceae has markedly larger genome sizes and remains the last major plant clade for which no chromosome-level assembly has been available. Here, we present chromosomal genome assemblies for two homosporous lycophyte species, the allotetraploid and the diploid .

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Background And Aims: Allopolyploidy is an important driver of diversification and a key contributor to genetic novelty across the tree of life. However, many studies have questioned the importance of extant polyploid lineages, suggesting that the vast majority may constitute evolutionary 'dead ends'. This has important implications for conservation efforts where polyploids and diploid progenitors often compete for wildlife management resources.

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Article Synopsis
  • Little is known about fern genomes, with only two small genomes published from Salviniales, but the genome of Alsophila spinulosa (flying spider-monkey tree fern) was assembled onto 69 pseudochromosomes.
  • This genome shows remarkable preservation of synteny due to an ancient whole-genome duplication over 100 million years ago, indicating the unique evolutionary path of tree ferns.
  • Investigations revealed insights into stem anatomy, lignin biosynthesis, identification of the compound alsophilin in xylem, and uncovered two genetic bottlenecks that led to population declines, highlighting the importance of A. spinulosa for understanding tree fern biology.
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Article Synopsis
  • Many plants in dry environments have developed a process called Crassulacean Acid Metabolism (CAM) to conserve water, but the aquatic plant Isoetes taiwanensis has also adapted this mechanism for low CO availability underwater.
  • This study generates a high-quality genome and RNA sequence data to explore CAM in Isoetes and finds significant similarities and key differences compared to terrestrial plants.
  • Notably, Isoetes uses a different type of PEPC for carbon fixation and shows divergent control of CAM genes, suggesting there are multiple evolutionary pathways to CAM that we are just beginning to understand.
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Horizontal gene transfer (HGT) has long been seen as a crucial process in the evolution of prokaryotic species, but until recently it was thought to have little, if any, effect on the evolution of eukaryotic life forms. Detecting and describing HGT events in eukaryotes is difficult, making this phenomenon at times controversial. However, modern advances in genomics and bioinformatics have radically altered our view of HGT in eukaryotes, especially in plants.

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Premise Of The Study: Although asexual taxa are generally seen as evolutionary dead ends, asexuality appears to provide a short-term benefit in some taxa, including a wider geographic distribution compared to sexual relatives. However, this may be an illusion created by multiple, morphologically cryptic, asexual lineages, each occupying a relatively small area. In this study we investigate the role of multiple lineages in the biogeography of Myriopteris gracilis Fée (Pteridaceae), a North American apomictic triploid fern species with a particularly large range.

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