Biodiversity genomics research requires reliable organismal identification, which can be difficult based on morphology alone. DNA-based identification using DNA barcoding can provide confirmation of species identity and resolve taxonomic issues but is rarely used in studies generating reference genomes. Here, we describe the development and implementation of DNA barcoding for the Darwin Tree of Life Project (DToL), which aims to sequence and assemble high quality reference genomes for all eukaryotic species in Britain and Ireland. We present a standardised framework for DNA barcode sequencing and data interpretation that is then adapted for diverse organismal groups. DNA barcoding data from over 12,000 DToL specimens has identified up to 20% of samples requiring additional verification, with 2% of seed plants and 3.5% of animal specimens subsequently having their names changed. We also make recommendations for future developments using new sequencing approaches and streamlined bioinformatic approaches.
A working checklist of accepted taxa worldwide is vital in achieving the goal of developing an online flora of all known plants by 2020 as part of the Global Strategy for Plant Conservation. We here present the first-ever worldwide checklist for liverworts (Marchantiophyta) and hornworts (Anthocerotophyta) that includes 7486 species in 398 genera representing 92 families from the two phyla. The checklist has far reaching implications and applications, including providing a valuable tool for taxonomists and systematists, analyzing phytogeographic and diversity patterns, aiding in the assessment of floristic and taxonomic knowledge, and identifying geographical gaps in our understanding of the global liverwort and hornwort flora. The checklist is derived from a working data set centralizing nomenclature, taxonomy and geography on a global scale. Prior to this effort a lack of centralization has been a major impediment for the study and analysis of species richness, conservation and systematic research at both regional and global scales. The success of this checklist, initiated in 2008, has been underpinned by its community approach involving taxonomic specialists working towards a consensus on taxonomy, nomenclature and distribution.
Premise: Bryophytes form a major component of terrestrial plant biomass, structuring ecological communities in all biomes. Our understanding of the evolutionary history of hornworts, liverworts, and mosses has been significantly reshaped by inferences from molecular data, which have highlighted extensive homoplasy in various traits and repeated bursts of diversification. However, the timing of key events in the phylogeny, patterns, and processes of diversification across bryophytes remain unclear.Methods: Using the GoFlag probe set, we sequenced 405 exons representing 228 nuclear genes for 531 species from 52 of the 54 orders of bryophytes. We inferred the species phylogeny from gene tree analyses using concatenated and coalescence approaches, assessed gene conflict, and estimated the timing of divergences based on 29 fossil calibrations.Results: The phylogeny resolves many relationships across the bryophytes, enabling us to resurrect five liverwort orders and recognize three more and propose 10 new orders of mosses. Most orders originated in the Jurassic and diversified in the Cretaceous or later. The phylogenomic data also highlight topological conflict in parts of the tree, suggesting complex processes of diversification that cannot be adequately captured in a single gene‐tree topology.Conclusions: We sampled hundreds of loci across a broad phylogenetic spectrum spanning at least 450 Ma of evolution; these data resolved many of the critical nodes of the diversification of bryophytes. The data also highlight the need to explore the mechanisms underlying the phylogenetic ambiguity at specific nodes. The phylogenomic data provide an expandable framework toward reconstructing a comprehensive phylogeny of this important group of plants.
Royal Botanic Garden Edinburgh Genome Acquisition Lab
DCDarwin Tree of Life Consortium
Darwin Tree of Life Consortium
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We present a genome assembly from an individual Malus sylvestris (the European or 'wild' crab apple; Streptophyta; Magnoliopsida; Rosales; Rosaceae). The genome sequence is 642 megabases in span. Most of the assembly (99.98%) is scaffolded into 17 chromosomal pseudomolecules. The mitochondrial and chloroplast genomes were also assembled, with respective lengths of 396.9 kilobases and 160.0 kilobases.