Publications by authors named "Alex Twyford"

Most studies investigating the genomic nature of species differences anticipate monophyletic species with genome-wide differentiation. However, this may not be the case at the earliest stages of speciation where reproductive isolation is weak and homogenising gene flow blurs species boundaries. We investigate genomic differences between species in a postglacial radiation of eyebrights (Euphrasia), a taxonomically complex plant group with variation in ploidy and mating system.

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We present a genome assembly from a tetraploid specimen of the confused eyebright, (Streptophyta; Magnoliopsida; Lamiales; Orobanchaceae). The genome sequence has a total length of 976.50 megabases.

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We present a genome assembly from a specimen of small nettle, (Streptophyta; Magnoliopsida; Rosales; Urticaceae). The genome sequence has a total length of 339.60 megabases.

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We present a genome assembly from an individual of (Streptophyta; Magnoliopsida; Fabales; Fabaceae). The genome sequence has a total length of 970.60 megabases.

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We present a genome assembly from an individual of (Streptophyta; Magnoliopsida; Fabales; Fabaceae). The genome sequence has a total length of 899.60 megabases.

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We present a genome assembly from an individual of (Streptophyta; Magnoliopsida; Fabales; Fabaceae). The genome sequence has a total length of 948.00 megabases.

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Article Synopsis
  • - The Darwin Tree of Life Project (DToL) focuses on sequencing high-quality genomes for all eukaryotic species in Britain and Ireland, highlighting the importance of accurate organism identification through DNA barcoding.
  • - DNA barcoding offers a reliable method for species identification and resolving taxonomic ambiguities, but it has not been widely used in projects creating reference genomes until this initiative.
  • - The project analyzed over 12,000 specimens, revealing that up to 20% needed further verification, leading to name changes for 2% of seed plants and 3.5% of animal specimens, while also suggesting improvements for future sequencing and data analysis.
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We present a genome assembly from a diploid female (the Annual Mercury; Tracheophyta; Magnoliopsida; Malpighiales; Euphorbiaceae). The genome sequence is 453.2 megabases in span.

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Natural hybridisation is now recognised as pervasive in its occurrence across the Tree of Life. Resurgent interest in natural hybridisation fuelled by developments in genomics has led to an improved understanding of the genetic factors that promote or prevent species cross-mating. Despite this body of work overturning many widely held assumptions about the genetic barriers to hybridisation, it is still widely thought that ploidy differences between species will be an absolute barrier to hybridisation and introgression.

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We present a genome assembly from a specimen of (common ivy; Streptophyta; Magnoliopsida; Apiales; Araliaceae). The genome sequence is 1,199.4 megabases in span.

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Background And Aims: Exploring how species diverge is vital for understanding the drivers of speciation. Factors such as geographical separation and ecological selection, hybridization, polyploidization and shifts in mating system are all major mechanisms of plant speciation, but their contributions to divergence are rarely well understood. Here we test these mechanisms in two plant species, Gentiana lhassica and G.

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In intimate ecological interactions, the interdependency of species may result in correlated demographic histories. For species of conservation concern, understanding the long-term dynamics of such interactions may shed light on the drivers of population decline. Here, we address the demographic history of the monarch butterfly, Danaus plexippus, and its dominant host plant, the common milkweed Asclepias syriaca (A.

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A role of ecological adaptation in speciation can be obscured by stochastic processes and differences that species accumulate after genetic isolation. One way to identify adaptive characters and their underlying genes is to study cases of speciation involving parallel adaptations. Recently resolved phylogenies reveal that alpine morphology has evolved in parallel in the genus Antirrhinum (snapdragons): first in an early split of an alpine from a lowland lineage and, more recently, from within the lowland lineage to produce closely related sympatric species with contrasting alpine and lowland forms.

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Natural hybridization can have a profound evolutionary impact, with consequences ranging from the extinction of rare taxa to the origin of new species. Natural hybridization is particularly common in plants; however, our understanding of the general factors that promote or prevent hybridization is hampered by the highly variable outcomes in different lineages. Here, we quantify the influence of different predictors on hybrid formation across species from an entire flora.

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Premise: Strong postzygotic reproductive isolating barriers are usually expected to limit the extent of natural hybridization between species with contrasting ploidy. However, genomic sequencing has revealed previously overlooked examples of natural cross-ploidy hybridization in some flowering plant genera, suggesting that the phenomenon may be more common than once thought. We investigated potential cross-ploidy hybridization in British eyebrights (Euphrasia, Orobanchaceae), a group from which 13 putative cross-ploidy hybrid combinations have been reported based on morphology.

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Article Synopsis
  • Understanding population differentiation and speciation helps explain biodiversity, particularly in the Hengduan Mountains, which has a rich and unique plant life.
  • Researchers used advanced DNA sequencing to analyze genetic variations in the Gentianaceae family, discovering distinct genetic clusters based on geography within the mountains.
  • Findings revealed significant genetic differentiation between Southern and Northern populations, with the complex originating in central HM and dispersing during specific geological epochs, influenced by geographic barriers and climatic changes.
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Genome size variation within plant taxa is due to presence/absence variation, which may affect low-copy sequences or genomic repeats of various frequency classes. However, identifying the sequences underpinning genome size variation is challenging because genome assemblies commonly contain collapsed representations of repetitive sequences and because genome skimming studies by design miss low-copy number sequences. Here, we take a novel approach based on k-mers, short sub-sequences of equal length , generated from whole-genome sequencing data of diploid eyebrights (), a group of plants that have considerable genome size variation within a ploidy level.

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Disentangling the phylogenetic relationships of taxonomically complex plant groups is often mired by challenges associated with recent speciation, hybridization, complex mating systems, and polyploidy. Here, we perform a phylogenomic analysis of eyebrights (), a group renowned for taxonomic complexity, with the aim of documenting the extent of phylogenetic discordance at both deep and at shallow phylogenetic scales. We generate whole-genome sequencing data and integrate this with prior genomic data to perform a comprehensive analysis of nuclear genomic, nuclear ribosomal (nrDNA), and complete plastid genomes from 57 individuals representing 36 species.

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Cape Primroses (, Gesneriaceae) are an ideal study system for investigating the genetics underlying species diversity in angiosperms. has served as a model species for plant developmental research for over five decades due to its unusual extended meristem activity present in the leaves. In this study, we sequenced and assembled the complete nuclear, chloroplast, and mitochondrial genomes of using Oxford Nanopore Technologies long read sequencing.

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Many diverse plant clades possess bilaterally symmetrical flowers and specialised pollination syndromes, suggesting that these traits may promote diversification. We examined the evolution of diverse floral morphologies in a species-rich tropical radiation of Rhododendron. We used restriction-site associated DNA sequencing on 114 taxa from Rhododendron sect.

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The vascular flora of Britain and Ireland is among the most extensively studied in the world, but the current knowledge base is fragmentary, with taxonomic, ecological and genetic information scattered across different resources. Here we present the first comprehensive data repository of native and alien species optimized for fast and easy online access for ecological, evolutionary and conservation analyses. The inventory is based on the most recent reference flora of Britain and Ireland, with taxon names linked to unique Kew taxon identifiers and DNA barcode data.

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Angiosperms possess various strategies to ensure reproductive success, such as stylar polymorphisms that encourage outcrossing. Here, we investigate the genetic basis of one such dimorphism that combines both temporal and spatial separation of sexual function, termed flexistyly. It is a floral strategy characterised by the presence of two morphs that differ in the timing of stylar movement.

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Generalist hemiparasites may attach to many different host species and experience complex parasite-host interactions. How these parasite-host interactions impact on the fitness of hemiparasitic plants remain largely unknown. We used experimentally tractable eyebrights (Euphrasia, Orobanchaceae) to understand parasite-host species interactions affecting the performance of a generalist hemiparasitic plant.

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Background And Aims: Genome size varies considerably across the diversity of plant life. Although genome size is, by definition, affected by genetic presence/absence variants, which are ubiquitous in population sequencing studies, genome size is often treated as an intrinsic property of a species. Here, we studied intra- and interspecific genome size variation in taxonomically complex British eyebrights (Euphrasia, Orobanchaceae).

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Parallel evolution of similar morphologies in closely related lineages provides insight into the repeatability and predictability of evolution. In the genus Antirrhinum (snapdragons), as in other plants, a suite of morphological characters are associated with adaptation to alpine environments. We tested for parallel trait evolution in Antirrhinum by investigating phylogenetic relationships using restriction-site associated DNA (RAD) sequencing.

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