153 research outputs found

    Phylogeny and evolution of anomalous roots in Daviesia (Fabaceae : Mirbelieae)

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    The phylogeny of the Australian legume genus Daviesia was estimated using sequences of the internal transcribed spacers of nuclear ribosomal DNA. Partial congruence was found with previous analyses using morphology, including strong support for monophyly of the genus and for a sister group relationship between the clade D. pachyloma and the rest of the genus. A previously unplaced bird-pollinated species, anceps + D. D. epiphyllum, was well supported as sister to the only other bird-pollinated species in the genus, D. speciosa, indicating a single origin of bird pollination in their common ancestor. Other morphological groups within Daviesia were not supported and require reassessment. A strong and previously unreported sister clade of Daviesia consists of the two monotypic genera Erichsenia and Viminaria. These share phyllode-like leaves and indehiscent fruits. The evolutionary history of cord roots, which have anomalous secondary thickening, was explored using parsimony. Cord roots are limited to three separate clades but have a complex history involving a small number of gains (most likely 0-3) and losses (0-5). The anomalous structure of cord roots ( adventitious vascular strands embedded in a parenchymatous matrix) may facilitate nutrient storage, and the roots may be contractile. Both functions may be related to a postfire resprouting adaptation. Alternatively, cord roots may be an adaptation to the low-nutrient lateritic soils of Western Australia. However, tests for association between root type, soil type, and growth habit were equivocal, depending on whether the variables were treated as phylogenetically dependent (insignificant) or independent ( significant)

    Evolutionary consequences of shifts to bird-pollination in the Australian pea-flowered legumes (Mirbelieae and Bossiaeeae)

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    BACKGROUND Interactions with pollinators are proposed to be one of the major drivers of diversity in angiosperms. Specialised interactions with pollinators can lead to specialised floral traits, which collectively are known as a pollination syndrome. While it is thought that specialisation to a pollinator can lead to either an increase in diversity or in some cases a dead end, it is not well understood how transitions among specialised pollinators contribute to changes in diversity. Here, we use evolutionary trait reconstruction of bee-pollination and bird-pollination syndromes in Australian egg-and-bacon peas (Mirbelieae and Bossiaeeae) to test whether transitions between pollination syndromes is correlated with changes in species diversity. We also test for directionality in transitions that might be caused by selection by pollinators or by an evolutionary ratchet in which reversals to the original pollination syndrome are not possible. RESULTS Trait reconstructions of Australian egg-and-bacon peas suggest that bee-pollination syndrome is the ancestral form and that there has been replicated evolution of bird-pollination syndromes. Reconstructions indicate potential reversals from bird- to bee-pollination syndromes but this is not consistent with morphology. Species diversity of bird-pollination syndrome clades is lower than that of their bee-pollination syndrome sisters.We estimated the earliest transitions from bee- to bird-pollination syndrome occurred between 30.8 Ma and 10.4 Ma. Geographical structuring of pollination syndromes was found; there were fewer bird-pollination species in the Australian southeast temperate region compared to other regions of Australia. CONCLUSIONS A consistent decrease in diversification rate coincident with switches to bird pollination might be explained if greater dispersal by bird pollinators results in higher levels of connectivity among populations and reduced chances of allopatric speciation.The earliest transitions overlap with the early diversification of Australian honeyeaters - the major lineage of pollinating birds in Australia. Our findings are consistent with the idea that environment and availability of pollinators are important in the evolution of pollination syndromes. Changes in flower traits as a result of transitions to bird-pollination syndrome might also limit reversals to a bee-pollination syndrome.Funding was provided by the Australian Research Council (grant number: DP0985473)

    Australia's arid-adapted butcherbirds experienced range expansions during Pleistocene glacial maxima

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    A model of range expansions during glacial maxima (GM) for cold-adapted species is generally accepted for the Northern Hemisphere. Given that GM in Australia largely resulted in the expansion of arid zones, rather than glaciation, it could be expected that arid-adapted species might have had expanded ranges at GM, as cold-adapted species did in the Northern Hemisphere. For Australian biota, however, it remains paradigmatic that arid-adapted species contracted to refugia at GM. Here we use multilocus data and ecological niche models (ENMs) to test alternative GM models for butcherbirds. ENMs, mtDNA and estimates of nuclear introgression and past population sizes support a model of GM expansion in the arid-tolerant Grey Butcherbird that resulted in secondary contact with its close relative - the savanna-inhabiting Silver-backed Butcherbird - whose contemporary distribution is widely separated. Together, these data reject the universal use of a GM contraction model for Australia's dry woodland and arid biota

    Australian processionary caterpillars, Ochrogaster lunifer Herrich‐Schäffer (Lepidoptera: Notodontidae), comprise cryptic species

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    The bag shelter moth, Ochrogaster lunifer Herrich-Schäffer, 1855 (Thaumetopoeinae), is abundant and widespread throughout Australia where its larvae have been reported to feed mostly on Acacia and eucalypts. The larvae, known as processionary caterpillars, build silken nests on their host plants either on the ground at the base of the plant (Acacia) or above ground on the trunk or among the canopy (Acacia and eucalypts). The caterpillars are medically important in that they shed tiny setae that can cause dermatitis and other health problems in humans and other mammals, including amnionitis and foetal loss in horses. Despite reports of behavioural, ecological and morphological differences between ground and canopy nesters, caterpillars of all nest types and hosts are currently considered to belong to one species. Here, we use DNA sequence data from the mitochondrial and nuclear genomes of caterpillars taken from different nest types in eastern Australia to determine whether there is evidence for there being more than one species. We find significant genetic divergence between caterpillars from different nest types despite occurrence in sympatry at multiple sites, indicative of a lack of gene flow and the presence of at least two reproductively isolated species. Given the range of hosts and nest locations within hosts throughout Australia, further sampling is needed to determine just how many species there are under the current concept of O.\ua0lunifer

    Identifying genetic markers for a range of phylogenetic utility–From species to family level

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    Resolving the phylogenetic relationships of closely related species using a small set of loci is challenging as sufficient information may not be captured from a limited sample of the genome. Relying on few loci can also be problematic when conflict between gene-trees arises from incomplete lineage sorting and/or ongoing hybridization, problems especially likely in recently diverged lineages. Here, we developed a method using limited genomic resources that allows identification of many low copy candidate loci from across the nuclear and chloroplast genomes, design probes for target capture and sequence the captured loci. To validate our method we present data from Eucalyptus and Melaleuca, two large and phylogenetically problematic genera within the Myrtaceae family. With one annotated genome, one transcriptome and two whole-genome shotgun sequences of one Eucalyptus and four Melaleuca species, respectively, we identified 212 loci representing 263 kbp for targeted sequence capture and sequencing. Of these, 209 were successfully tested from 47 samples across five related genera of Myrtaceae. The average percentage of reads mapped back to the reference was 57.6% with coverage of more than 20 reads per position across 83.5% of the data. The methods developed here should be applicable across a large range of taxa across all kingdoms. The core methods are very flexible, providing a platform for various genomic resource availabilities and are useful from shallow to deep phylogenies

    Identifying genetic markers for a range of phylogenetic utility–From species to family level

    Get PDF
    Resolving the phylogenetic relationships of closely related species using a small set of loci is challenging as sufficient information may not be captured from a limited sample of the genome. Relying on few loci can also be problematic when conflict between gene-trees arises from incomplete lineage sorting and/or ongoing hybridization, problems especially likely in recently diverged lineages. Here, we developed a method using limited genomic resources that allows identification of many low copy candidate loci from across the nuclear and chloroplast genomes, design probes for target capture and sequence the captured loci. To validate our method we present data from Eucalyptus and Melaleuca, two large and phylogenetically problematic genera within the Myrtaceae family. With one annotated genome, one transcriptome and two whole-genome shotgun sequences of one Eucalyptus and four Melaleuca species, respectively, we identified 212 loci representing 263 kbp for targeted sequence capture and sequencing. Of these, 209 were successfully tested from 47 samples across five related genera of Myrtaceae. The average percentage of reads mapped back to the reference was 57.6% with coverage of more than 20 reads per position across 83.5% of the data. The methods developed here should be applicable across a large range of taxa across all kingdoms. The core methods are very flexible, providing a platform for various genomic resource availabilities and are useful from shallow to deep phylogenies

    Comprehensive translational assessment of human-induced pluripotent stem cell derived cardiomyocytes for evaluating drug-induced arrhythmias

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    Induced pluripotent stem cell-derived cardiomyocytes (iPSC-CM) hold promise for assessment of drug-induced arrhythmias and are being considered for use under the comprehensive in vitro proarrhythmia assay (CiPA). We studied the effects of 26 drugs and 3 drug combinations on 2 commercially available iPSC-CM types using high-throughput voltage-sensitive dye and microelectrode-array assays being studied for the CiPA initiative and compared the results with clinical QT prolongation and torsade de pointes (TdP) risk. Concentration-dependent analysis comparing iPSC-CMs to clinical trial results demonstrated good correlation between drug-induced rate-corrected action potential duration and field potential duration (APDc and FPDc) prolongation and clinical trial QTc prolongation. Of 20 drugs studied that exhibit clinical QTc prolongation, 17 caused APDc prolongation (16 in Cor.4U and 13 in iCell cardiomyocytes) and 16 caused FPDc prolongation (16 in Cor.4U and 10 in iCell cardiomyocytes). Of 14 drugs that cause TdP, arrhythmias occurred with 10 drugs. Lack of arrhythmic beating in iPSC-CMs for the four remaining drugs could be due to differences in relative levels of expression of individual ion channels. iPSC-CMs responded consistently to human ether-a-go-go potassium channel blocking drugs (APD prolongation and arrhythmias) and calcium channel blocking drugs (APD shortening and prevention of arrhythmias), with a more variable response to late sodium current blocking drugs. Current results confirm the potential of iPSC-CMs for proarrhythmia prediction under CiPA, where iPSC-CM results would serve as a check to ion channel and in silico modeling prediction of proarrhythmic risk. A multi-site validation study is warranted

    Las competencias del Estado sobre otros espacios de interés internacional

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    PowerPoint del Tema 10 de la asignatura "Derecho Internacional Público". Curso 2017-18.Tema 10. Las competencias del Estado sobre otros espacios de interés internacional: 1.- Las vías de agua internacionales. 2.- Los espacios polares: el Ártico y la Antártida. 3.- El espacio ultraterrestre

    Perianth evolution and implications for generic delimitation in the eucalypts (Myrtaceae), including the description of the new genus, Blakella

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    Eucalypts (Myrtaceae tribe Eucalypteae) are currently placed in seven genera. Traditionally, Eucalyptus was defined by its operculum, but when phylogenies placed Angophora, with free sepals and petals, as sister to the operculate bloodwood eucalypts, the latter were segregated into a new genus, Corymbia. Yet, generic delimitation in the tribe Eucalypteae remains uncertain. Here, we address these problems using phylogenetic analysis with the largest molecular data set to date. We captured 101 low-copy nuclear exons from 392 samples representing 266 species. Our phylogenetic analysis used maximum likelihood (IQtree) and multispecies coalescent (Astral). At two nodes critical to generic delimitation, we tested alternative relationships among Arillastrum, Angophora, Eucalyptus, and Corymbia using Shimodaira\u27s approximately unbiased test. Phylogenetic mapping was used to explore the evolution of perianth traits. Monophyly of Corymbia relative to Angophora was decisively rejected. All alternative relationships among the seven currently recognized Eucalypteae genera imply homoplasy in the evolutionary origins of the operculum. Inferred evolutionary transitions in perianth traits are congruent with divergences between major clades, except that the expression of separate sepals and petals in Angophora, which is nested within the operculate genus Corymbia, appears to be a reversal to the plesiomorphic perianth structure. Here, we formally raise Corymbia subg. Blakella to genus rank and make the relevant new combinations. We also define and name three sections within Blakella (Blakella sect. Blakella, Blakella sect. Naviculares, and Blakella sect. Maculatae), and two series within Blakella sect. Maculatae (Blakella ser. Maculatae and Blakella ser. Torellianae). Corymbia is reduced to the red bloodwoods

    Revision of the Melanocytic Pathology Assessment Tool and Hierarchy for Diagnosis Classification Schema for Melanocytic Lesions: A Consensus Statement

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    IMPORTANCE A standardized pathology classification system for melanocytic lesions is needed to aid both pathologists and clinicians in cataloging currently existing diverse terminologies and in the diagnosis and treatment of patients. The Melanocytic Pathology Assessment Tool and Hierarchy for Diagnosis (MPATH-Dx) has been developed for this purpose. OBJECTIVE To revise the MPATH-Dx version 1.0 classification tool, using feedback from dermatopathologists participating in the National Institutes of Health-funded Reducing Errors in Melanocytic Interpretations (REMI) Study and from members of the International Melanoma Pathology Study Group (IMPSG). EVIDENCE REVIEW Practicing dermatopathologists recruited from 40 US states participated in the 2-year REMI study and provided feedback on the MPATH-Dx version 1.0 tool. Independently, member dermatopathologists participating in an IMPSG workshop dedicated to the MPATH-Dx schema provided additional input for refining the MPATH-Dx tool. A reference panel of 3 dermatopathologists, the original authors of the MPATH-Dx version 1.0 tool, integrated all feedback into an updated and refined MPATH-Dx version 2.0. FINDINGS The new MPATH-Dx version 2.0 schema simplifies the original 5-class hierarchy into 4 classes to improve diagnostic concordance and to provide more explicit guidance in the treatment of patients. This new version also has clearly defined histopathological criteria for classification of classes I and II lesions; has specific provisions for the most frequently encountered low-cumulative sun damage pathway of melanoma progression, as well as other, less common World Health Organization pathways to melanoma; provides guidance for classifying intermediate class II tumors vs melanoma; and recognizes a subset of pT1a melanomas with very low risk and possible eventual reclassification as neoplasms lacking criteria for melanoma. CONCLUSIONS AND RELEVANCE The implementation of the newly revised MPATH-Dx version 2.0 schema into clinical practice is anticipated to provide a robust tool and adjunct for standardized diagnostic reporting of melanocytic lesions and management of patients to the benefit of both health care practitioners and patients
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