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15
result(s) for
"Rich, Tim C. G."
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DNA Barcoding the Native Flowering Plants and Conifers of Wales
2012
We present the first national DNA barcode resource that covers the native flowering plants and conifers for the nation of Wales (1143 species). Using the plant DNA barcode markers rbcL and matK, we have assembled 97.7% coverage for rbcL, 90.2% for matK, and a dual-locus barcode for 89.7% of the native Welsh flora. We have sampled multiple individuals for each species, resulting in 3304 rbcL and 2419 matK sequences. The majority of our samples (85%) are from DNA extracted from herbarium specimens. Recoverability of DNA barcodes is lower using herbarium specimens, compared to freshly collected material, mostly due to lower amplification success, but this is balanced by the increased efficiency of sampling species that have already been collected, identified, and verified by taxonomic experts. The effectiveness of the DNA barcodes for identification (level of discrimination) is assessed using four approaches: the presence of a barcode gap (using pairwise and multiple alignments), formation of monophyletic groups using Neighbour-Joining trees, and sequence similarity in BLASTn searches. These approaches yield similar results, providing relative discrimination levels of 69.4 to 74.9% of all species and 98.6 to 99.8% of genera using both markers. Species discrimination can be further improved using spatially explicit sampling. Mean species discrimination using barcode gap analysis (with a multiple alignment) is 81.6% within 10×10 km squares and 93.3% for 2×2 km squares. Our database of DNA barcodes for Welsh native flowering plants and conifers represents the most complete coverage of any national flora, and offers a valuable platform for a wide range of applications that require accurate species identification.
Journal Article
Breeding system and spatial isolation from congeners strongly constrain seed set in an insect-pollinated apomictic tree: Sorbus subcuneata (Rosaceae)
2017
In plants, apomixis results in the production of clonal offspring via seed and can provide reproductive assurance for isolated individuals. However, many apomicts require pollination to develop functional endosperm for successful seed set (pseudogamy) and therefore risk pollination-limitation, particularly in self-incompatible species that require heterospecific pollen. We used microsatellite paternity analysis and hand pollinations to investigate pollen-limitation in
Sorbus subcuneata
, a threatened endemic tree that co-occurs with its congener,
S. admonitor
. We confirmed that
S. subcuneata
is an obligate pseudogamous apomict, but open-pollinated flowers rarely produced seed (flower-to-seed conversion < 1%) even though they rapidly accumulated pollen on their stigmas. Manual heterospecific pollination by
S. admonitor
resulted in a high flower-to-seed conversion rate (65%), however, we estimate that the ratio of self: heterospecific pollination in open-pollinated flowers was at least 22:1. Despite the efficacy of heterospecific pollination, the contribution of
S. admonitor
trees to paternity in seed from open-pollinated flowers of
S. subcuneata
decreased rapidly with the spatial separation between paternal and maternal trees. Conservation efforts aimed at maintaining species with this breeding system must therefore manage the congeners in tandem which will also maintain the potential for rare heterospecific fertilisation that typically cause rapid diversification in these lineages.
Journal Article
Native and alien invasive plants: more of the same?
by
Thompson, Ken
,
Hodgson, John G.
,
Rich, Tim C. G.
in
Animal and plant ecology
,
Animal, plant and microbial ecology
,
Biological and medical sciences
1995
We compare the ecological and habitat characteristics of alien and native vascular plants which have recently expanded in range in England, Scotland, the Republic of Ireland and the Netherlands. In the great majority of respects, expanding aliens and natives are functionally indistinguishable. However, there are a few consistent differences: aliens are more likely than natives to be clonal, polycarpic perennials with erect, leafy stems, and to have transient seed banks. We discuss these trends in the context of the difficulties faced by aliens in invading mostly closed plant communities in relatively cool, damp climates. Our results are consistent with some predictions of the attributes of 'ideal' invaders, but contradict others. We argue that the ecological attributes of successful alien invaders are strongly habitat-dependent.
Journal Article
Current knowledge, status, and future for plant and fungal diversity in Great Britain and the UK Overseas Territories
2020
We rely on plants and fungi for most aspects of our lives. Yet plants and fungi are under threat, and we risk losing species before we know their identity, roles, and potential uses. Knowing names, distributions and threats are first steps towards effective conservation action. Accessible products like field guides and online resources engage society, harnessing collective support for conservation. Here we review current knowledge of the plants and fungi of the UK and UK Overseas Territories, highlighting gaps to help direct future research efforts towards conserving these vital elements of biodiversity. Societal Impact Statement We rely on plants and fungi for most aspects of our lives. Yet plants and fungi are under threat, and we risk losing species before we know their identity, roles, and potential uses. Knowing names, distributions, and threats are first steps toward effective conservation action. Accessible products like field guides and online resources engage society, harnessing collective support for conservation. Here, we review current knowledge of the plants and fungi of the UK and UK Overseas Territories, highlighting gaps to help direct future research efforts toward conserving these vital elements of biodiversity. Summary This review summarizes current knowledge of the status and threats to the plants and fungi of Great Britain and the UK Overseas Territories (UKOTs). Although the body of knowledge is considerable, the distribution of information varies substantially, and we highlight knowledge gaps. The UK vascular flora is the most well studied and we have a relatively clear picture of its 9,001 native and alien taxa. We have seedbanked 72% of the native and archaeophyte angiosperm taxa and 78% of threatened taxa. Knowledge of the UKOTs flora varies across territories and we report a UKOTs flora comprising 4,093 native and alien taxa. We have conserved 56% of the native flora and 51% of the threatened vascular plants in Kew's Millennium Seed Bank, UK. We need a better understanding of the conservation status of plants in the wild, and progress toward completion or updating national red lists varies. Site‐based protection of key plant assemblages is outlined, and progress in identifying Important Plant Areas analyzed. Knowledge of the non‐vascular flora, especially seaweeds remains patchy, particularly in many UKOTs. The biggest gaps overall are in fungi, particularly non‐lichenized fungi. Considerable investment is needed to fill these knowledge gaps and instigate effective conservation strategies.
Journal Article
Typification of Some T. Hedlund Names in Sorbus L. (Rosaceae)
2006
Teodor Hedlund was a Swedish botanist who published nearly 50 new names or combinations in Sorbus L. (Rosaceae). Lectotypes are designated for Sorbus arranensis Hedlund, S. minima (Ley) Hedlund, S. quercifolia Hedlund and S. subsimilis Hedlund. The lectotypification of S. anglica Hedlund by A. J. Wilmott is rejected and a new lectotype selected. Notes are given on typification of S. rupicola (Syme) Hedlund. \"Sorbus globulifera Hedlund ex Riddelsdell\" is not validly published and the material it is based on is part of the variation in S. aria (L.) Crantz.
Journal Article
Ecology and molecular targets of hypermutation in the global microbiome
2021
Changes in the sequence of an organism’s genome, i.e., mutations, are the raw material of evolution. The frequency and location of mutations can be constrained by specific molecular mechanisms, such as diversity-generating retroelements (DGRs). DGRs have been characterized from cultivated bacteria and bacteriophages, and perform error-prone reverse transcription leading to mutations being introduced in specific target genes. DGR loci were also identified in several metagenomes, but the ecological roles and evolutionary drivers of these DGRs remain poorly understood. Here, we analyze a dataset of >30,000 DGRs from public metagenomes, establish six major lineages of DGRs including three primarily encoded by phages and seemingly used to diversify host attachment proteins, and demonstrate that DGRs are broadly active and responsible for >10% of all amino acid changes in some organisms. Overall, these results highlight the constraints under which DGRs evolve, and elucidate several distinct roles these elements play in natural communities.
Here, the authors report a large-scale comparative analysis of <30,000 Diversity-Generating Retroelements (DGRs) across ~9000 metagenomes (representing diverse taxa and biomes), to identify patterns in terms of prevalence and activity. Combined with examination of longitudinal data on <100 metagenomes part of time series, they demonstrate that DGRs are broadly and consistently active, implying an important role in microbiota ecology and evolution.
Journal Article
Meningioma DNA methylation groups identify biological drivers and therapeutic vulnerabilities
by
Magill, Stephen T.
,
Schulte, Jessica D.
,
Lucas, Calixto-Hope G.
in
631/208/176
,
631/67/1059/602
,
631/67/1857
2022
Meningiomas are the most common primary intracranial tumors. There are no effective medical therapies for meningioma patients, and new treatments have been encumbered by limited understanding of meningioma biology. Here, we use DNA methylation profiling on 565 meningiomas integrated with genetic, transcriptomic, biochemical, proteomic and single-cell approaches to show meningiomas are composed of three DNA methylation groups with distinct clinical outcomes, biological drivers and therapeutic vulnerabilities. Merlin-intact meningiomas (34%) have the best outcomes and are distinguished by
NF2
/Merlin regulation of susceptibility to cytotoxic therapy. Immune-enriched meningiomas (38%) have intermediate outcomes and are distinguished by immune infiltration,
HLA
expression and lymphatic vessels. Hypermitotic meningiomas (28%) have the worst outcomes and are distinguished by convergent genetic and epigenetic mechanisms driving the cell cycle and resistance to cytotoxic therapy. To translate these findings into clinical practice, we show cytostatic cell cycle inhibitors attenuate meningioma growth in cell culture, organoids, xenografts and patients.
DNA methylation profiling of 565 meningiomas highlights three groups associated with distinct molecular, clinical and therapeutic features.
Journal Article
Chromosome Xq23 is associated with lower atherogenic lipid concentrations and favorable cardiometabolic indices
by
O’Connell, Jeffrey R.
,
Aslibekyan, Stella
,
Moon, Jee-Young
in
45/43
,
631/208/205/2138
,
692/4019/592/2727
2021
Autosomal genetic analyses of blood lipids have yielded key insights for coronary heart disease (CHD). However, X chromosome genetic variation is understudied for blood lipids in large sample sizes. We now analyze genetic and blood lipid data in a high-coverage whole X chromosome sequencing study of 65,322 multi-ancestry participants and perform replication among 456,893 European participants. Common alleles on chromosome Xq23 are strongly associated with reduced total cholesterol, LDL cholesterol, and triglycerides (min
P
= 8.5 × 10
−72
), with similar effects for males and females. Chromosome Xq23 lipid-lowering alleles are associated with reduced odds for CHD among 42,545 cases and 591,247 controls (
P
= 1.7 × 10
−4
), and reduced odds for diabetes mellitus type 2 among 54,095 cases and 573,885 controls (
P
= 1.4 × 10
−5
). Although we observe an association with increased BMI, waist-to-hip ratio adjusted for BMI is reduced, bioimpedance analyses indicate increased gluteofemoral fat, and abdominal MRI analyses indicate reduced visceral adiposity. Co-localization analyses strongly correlate increased
CHRDL1
gene expression, particularly in adipose tissue, with reduced concentrations of blood lipids.
The influence of X chromosome genetic variation on blood lipids and coronary heart disease (CHD) is not well understood. Here, the authors analyse X chromosome sequencing data across 65,322 multi-ancestry individuals, identifying associations of the Xq23 locus with lipid changes and reduced risk of CHD and diabetes mellitus.
Journal Article