296 research outputs found

    Contingent Convergence: The Ability To Detect Convergent Genomic Evolution Is Dependent on Population Size and Migration

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    This is the author accepted manuscript. The final version is available from the Genetics Society of America via the DOI in this recordData availability: A full set of scripts including all bash, Eidos and R scripts necessary to repeat this analysis can be downloaded from Github (https://github.com/JimWhiting91/Contingent_Convergence_Pipeline). Supplementary figures (S1-49) have been uploaded through the GSA figshare portal. Supplementary figures include results for different mutation/recombination rates, PhenoNull and neutral data across sampling generations along with additional figures.Outlier scans, in which the genome is scanned for signatures of selection, have become a prominent tool in studies of local adaptation, and more recently studies of genetic convergence in natural populations. However, such methods have the potential to be confounded by features of demographic history, such as population size and migration, which are considerably varied across natural populations. In this study, we use forward-simulations to investigate and illustrate how several measures of genetic differentiation commonly used in outlier scans (FST, DXY and Δπ) are influenced by demographic variation across multiple sampling generations. In a factorial design with 16 treatments, we manipulate the presence/absence of founding bottlenecks (N of founding individuals), prolonged bottlenecks (proportional size of diverging population) and migration rate between two populations with ancestral and diverged phenotypic optima. Our results illustrate known constraints of individual measures associated with reduced population size and a lack of migration; but notably we demonstrate how relationships between measures are similarly dependent on these features of demography. We find that false-positive signals of convergent evolution (the same simulated outliers detected in independent treatments) are attainable as a product of similar population size and migration treatments (particularly for DXY), and that outliers across different measures (for e.g. FST and DXY) can occur with little influence of selection. Taken together, we show how underappreciated, yet quantifiable measures of demographic history can influence commonly employed methods for detecting selection.European Research Council (ERC

    Drainage-structuring of ancestral variation and a common functional pathway shape limited genomic convergence in natural high- and low-predation guppies

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    This is the final version. Available from Public Library of Science via the DOI in this record. Data Availability: Raw sequencing reads are available on ENA: PRJEB43917 (Aripo, Madamas, Tacarigua) and PRJEB10680 (Guanapo and Oropouche). Final VCF data are available on FigShare, doi: 10.6084/m9.figshare.14315771. Other data and scripts used to analyse data are available on github: github.com/JimWhiting91/guppy_convergence. This repository is archived with Zenodo, doi: 10.5281/zenodo.4740381.Studies of convergence in wild populations have been instrumental in understanding adaptation by providing strong evidence for natural selection. At the genetic level, we are beginning to appreciate that the re-use of the same genes in adaptation occurs through different mechanisms and can be constrained by underlying trait architectures and demographic characteristics of natural populations. Here, we explore these processes in naturally adapted high- (HP) and low-predation (LP) populations of the Trinidadian guppy, Poecilia reticulata. As a model for phenotypic change this system provided some of the earliest evidence of rapid and repeatable evolution in vertebrates; the genetic basis of which has yet to be studied at the whole-genome level. We collected whole-genome sequencing data from ten populations (176 individuals) representing five independent HP-LP river pairs across the three main drainages in Northern Trinidad. We evaluate population structure, uncovering several LP bottlenecks and variable between-river introgression that can lead to constraints on the sharing of adaptive variation between populations. Consequently, we found limited selection on common genes or loci across all drainages. Using a pathway type analysis, however, we find evidence of repeated selection on different genes involved in cadherin signaling. Finally, we found a large repeatedly selected haplotype on chromosome 20 in three rivers from the same drainage. Taken together, despite limited sharing of adaptive variation among rivers, we found evidence of convergent evolution associated with HP-LP environments in pathways across divergent drainages and at a previously unreported candidate haplotype within a drainage.H2020 European Research CouncilNatural Environment Research Counci

    On the genetic architecture of rapidly adapting and convergent life history traits in guppies

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    This is the final version. Available on open access from Springer Nature via the DOI in this recordData availability: All sequencing read data are available from the ENA (Study accession: PRJEB48691). All scripts and other data associated with analysis are available on GitHub (github.com/JimWhiting91/guppy_LH_QTL) and are archived on Zenodo (https://doi.org/10.5281/zenodo.5938562). The VCF, phenotypes, and linkage map are deposited with dryad (https://doi.org/10.5061/dryad.w3r2280sk).The genetic basis of traits shapes and constrains how adaptation proceeds in nature; rapid adaptation can proceed using stores of polygenic standing genetic variation or hard selective sweeps, and increasing polygenicity fuels genetic redundancy, reducing gene re-use (genetic convergence). Guppy life history traits evolve rapidly and convergently among natural high- and low-predation environments in northern Trinidad. This system has been studied extensively at the phenotypic level, but little is known about the underlying genetic architecture. Here, we use four independent F2 QTL crosses to examine the genetic basis of seven (five female, two male) guppy life history phenotypes and discuss how these genetic architectures may facilitate or constrain rapid adaptation and convergence. We use RAD-sequencing data (16,539 SNPs) from 370 male and 267 female F2 individuals. We perform linkage mapping, estimates of genome-wide and per-chromosome heritability (multi-locus associations), and QTL mapping (single-locus associations). Our results are consistent with architectures of many loci of small-effect for male age and size at maturity and female interbrood period. Male trait associations are clustered on specific chromosomes, but female interbrood period exhibits a weak genome-wide signal suggesting a potentially highly polygenic component. Offspring weight and female size at maturity are also associated with a single significant QTL each. These results suggest rapid, repeatable phenotypic evolution of guppies may be facilitated by polygenic trait architectures, but subsequent genetic redundancy may limit gene re-use across populations, in agreement with an absence of strong signatures of genetic convergence from recent analyses of wild guppies.European Research Council (ERC)Natural Environment Research Council (NERC)National Science Foundation (NSF)Wellcome TrustBiotechnology and Biological Sciences Research Council (BBSRC

    On the genetic architecture of rapidly adapting and convergent life history traits in guppies

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    This is the final version. Available on open access from Springer Nature via the DOI in this recordData availability: All sequencing read data are available from the ENA (Study accession: PRJEB48691). All scripts and other data associated with analysis are available on GitHub (github.com/JimWhiting91/guppy_LH_QTL) and are archived on Zenodo (https://doi.org/10.5281/zenodo.5938562). The VCF, phenotypes, and linkage map are deposited with dryad (https://doi.org/10.5061/dryad.w3r2280sk).The genetic basis of traits shapes and constrains how adaptation proceeds in nature; rapid adaptation can proceed using stores of polygenic standing genetic variation or hard selective sweeps, and increasing polygenicity fuels genetic redundancy, reducing gene re-use (genetic convergence). Guppy life history traits evolve rapidly and convergently among natural high- and low-predation environments in northern Trinidad. This system has been studied extensively at the phenotypic level, but little is known about the underlying genetic architecture. Here, we use four independent F2 QTL crosses to examine the genetic basis of seven (five female, two male) guppy life history phenotypes and discuss how these genetic architectures may facilitate or constrain rapid adaptation and convergence. We use RAD-sequencing data (16,539 SNPs) from 370 male and 267 female F2 individuals. We perform linkage mapping, estimates of genome-wide and per-chromosome heritability (multi-locus associations), and QTL mapping (single-locus associations). Our results are consistent with architectures of many loci of small-effect for male age and size at maturity and female interbrood period. Male trait associations are clustered on specific chromosomes, but female interbrood period exhibits a weak genome-wide signal suggesting a potentially highly polygenic component. Offspring weight and female size at maturity are also associated with a single significant QTL each. These results suggest rapid, repeatable phenotypic evolution of guppies may be facilitated by polygenic trait architectures, but subsequent genetic redundancy may limit gene re-use across populations, in agreement with an absence of strong signatures of genetic convergence from recent analyses of wild guppies.European Research Council (ERC)Natural Environment Research Council (NERC)National Science Foundation (NSF)Wellcome TrustBiotechnology and Biological Sciences Research Council (BBSRC

    Rapid genomic convergent evolution in experimental populations of Trinidadian guppies (Poecilia reticulata)

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    This is the final version. Available on open access from Wiley via the DOI in this recordData archiving: The data that support these findings are openly available at: European Nucleotide Archive (https://www.ebi.ac.uk/ena/ browser/home)—reference numbers: PRJEB42705 (all introduction populations) and PRJEB10680 (GHP). All scripts and associated data are available on Github repository: mapping and SNP calling (https://github.com/josieparis/gatk-snp-calling); population genomics and haplotype scans (https://github.com/ bfraser-commits/Rapid_genomic_adaptation_guppies); the software for multivariate AF analyses (AF-vapeR) (https://github. com/JimWhiting91/afvaper); and simulation analyses (https:// github.com/JimWhiting91/fibr_simulations).Although rapid phenotypic evolution has been documented often, the genomic basis of rapid adaptation to natural environments is largely unknown in multicellular organisms. Population genomic studies of experimental populations of Trinidadian guppies (Poecilia reticulata) provide a unique opportunity to study this phenomenon. Guppy populations that were transplanted from high-predation (HP) to low-predation (LP) environments have been shown to evolve toward the phenotypes of naturally colonized LP populations in as few as eight generations. These changes persist in common garden experiments, indicating that they have a genetic basis. Here, we report results of whole genome variation in four experimental populations colonizing LP sites along with the corresponding HP source population. We examined genome-wide patterns of genetic variation to estimate past demography and used a combination of genome scans, forward simulations, and a novel analysis of allele frequency change vectors to uncover the signature of selection. We detected clear signals of population growth and bottlenecks at the genome-wide level that matched the known history of population numbers. We found a region on chromosome 15 under strong selection in three of the four populations and with our multivariate approach revealing subtle parallel changes in allele frequency in all four populations across this region. Investigating patterns of genome-wide selection in this uniquely replicated experiment offers remarkable insight into the mechanisms underlying rapid adaptation, providing a basis for comparison with other species and populations experiencing rapidly changing environments.Max Planck SocietyEuropean Research Council (ERC)Natural Environment Research Council (NERC)University of SussexUniversity of ExeterNational Science Foundation (NSF

    One-loop Renormalization of Black Hole Entropy Due to Non-minimally Coupled Matter

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    The quantum entanglement entropy of an eternal black hole is studied. We argue that the relevant Euclidean path integral is taken over fields defined on α\alpha-fold covering of the black hole instanton. The statement that divergences of the entropy are renormalized by renormalization of gravitational couplings in the effective action is proved for non-minimally coupled scalar matter. The relationship of entanglement and thermodynamical entropies is discussed.Comment: 17 pages, latex, no figure

    Accuracy and repeatability of wrist joint angles in boxing using an electromagnetic tracking system

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    © 2019, The Author(s). The hand-wrist region is reported as the most common injury site in boxing. Boxers are at risk due to the amount of wrist motions when impacting training equipment or their opponents, yet we know relatively little about these motions. This paper describes a new method for quantifying wrist motion in boxing using an electromagnetic tracking system. Surrogate testing procedure utilising a polyamide hand and forearm shape, and in vivo testing procedure utilising 29 elite boxers, were used to assess the accuracy and repeatability of the system. 2D kinematic analysis was used to calculate wrist angles using photogrammetry, whilst the data from the electromagnetic tracking system was processed with visual 3D software. The electromagnetic tracking system agreed with the video-based system (paired t tests) in both the surrogate ( 0.9). In the punch testing, for both repeated jab and hook shots, the electromagnetic tracking system showed good reliability (ICCs > 0.8) and substantial reliability (ICCs > 0.6) for flexion–extension and radial-ulnar deviation angles, respectively. The results indicate that wrist kinematics during punching activities can be measured using an electromagnetic tracking system

    Further investigation of confirmed urinary tract infection (UTI) in children under five years: a systematic review.

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    Background: Further investigation of confirmed UTI in children aims to prevent renal scarring and future complications. Methods: We conducted a systematic review to determine the most effective approach to the further investigation of confirmed urinary tract infection (UTI) in children under five years of age. Results: 73 studies were included. Many studies had methodological limitations or were poorly reported. Effectiveness of further investigations: One study found that routine imaging did not lead to a reduction in recurrent UTIs or renal scarring. Diagnostic accuracy: The studies do not support the use of less invasive tests such as ultrasound as an alternative to renal scintigraphy, either to rule out infection of the upper urinary tract (LR- = 0.57, 95%CI: 0.47, 0.68) and thus to exclude patients from further investigation or to detect renal scarring (LR+ = 3.5, 95% CI: 2.5, 4.8). None of the tests investigated can accurately predict the development of renal scarring. The available evidence supports the consideration of contrast-enhanced ultrasound techniques for detecting vesico-ureteric reflux (VUR), as an alternative to micturating cystourethrography (MCUG) (LR+ = 14.1, 95% CI: 9.5, 20.8; LR- = 0.20, 95%CI: 0.13, 0.29); these techniques have the advantage of not requiring exposure to ionising radiation. Conclusion: There is no evidence to support the clinical effectiveness of routine investigation of children with confirmed UTI. Primary research on the effectiveness, in terms of improved patient outcome, of testing at all stages in the investigation of confirmed urinary tract infection is urgently required

    How does study quality affect the results of a diagnostic meta-analysis?

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    Background: The use of systematic literature review to inform evidence based practice in diagnostics is rapidly expanding. Although the primary diagnostic literature is extensive, studies are often of low methodological quality or poorly reported. There has been no rigorously evaluated, evidence based tool to assess the methodological quality of diagnostic studies. The primary objective of this study was to determine the extent to which variations in the quality of primary studies impact the results of a diagnostic meta-analysis and whether this differs with diagnostic test type. A secondary objective was to contribute to the evaluation of QUADAS, an evidence-based tool for the assessment of quality in diagnostic accuracy studies. Methods: This study was conducted as part of large systematic review of tests used in the diagnosis and further investigation of urinary tract infection (UTI) in children. All studies included in this review were assessed using QUADAS, an evidence-based tool for the assessment of quality in systematic reviews of diagnostic accuracy studies. The impact of individual components of QUADAS on a summary measure of diagnostic accuracy was investigated using regression analysis. The review divided the diagnosis and further investigation of UTI into the following three clinical stages: diagnosis of UTI, localisation of infection, and further investigation of the UTI. Each stage used different types of diagnostic test, which were considered to involve different quality concerns. Results: Many of the studies included in our review were poorly reported. The proportion of QUADAS items fulfilled was similar for studies in different sections of the review. However, as might be expected, the individual items fulfilled differed between the three clinical stages. Regression analysis found that different items showed a strong association with test performance for the different tests evaluated. These differences were observed both within and between the three clinical stages assessed by the review. The results of regression analyses were also affected by whether or not a weighting (by sample size) was applied. Our analysis was severely limited by the completeness of reporting and the differences between the index tests evaluated and the reference standards used to confirm diagnoses in the primary studies. Few tests were evaluated by sufficient studies to allow meaningful use of meta-analytic pooling and investigation of heterogeneity. This meant that further analysis to investigate heterogeneity could only be undertaken using a subset of studies, and that the findings are open to various interpretations. Conclusion: Further work is needed to investigate the influence of methodological quality on the results of diagnostic meta-analyses. Large data sets of well-reported primary studies are needed to address this question. Without significant improvements in the completeness of reporting of primary studies, progress in this area will be limited

    Sensitivity of the human auditory cortex to acoustic degradation of speech and non-speech sounds

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    The perception of speech is usually an effortless and reliable process even in highly adverse listening conditions. In addition to external sound sources, the intelligibility of speech can be reduced by degradation of the structure of speech signal itself, for example by digital compression of sound. This kind of distortion may be even more detrimental to speech intelligibility than external distortion, given that the auditory system will not be able to utilize sound source-specific acoustic features, such as spatial location, to separate the distortion from the speech signal. The perceptual consequences of acoustic distortions on speech intelligibility have been extensively studied. However, the cortical mechanisms of speech perception in adverse listening conditions are not well known at present, particularly in situations where the speech signal itself is distorted. The aim of this thesis was to investigate the cortical mechanisms underlying speech perception in conditions where speech is less intelligible due to external distortion or as a result of digital compression. In the studies of this thesis, the intelligibility of speech was varied either by digital compression or addition of stochastic noise. Cortical activity related to the speech stimuli was measured using magnetoencephalography (MEG). The results indicated that degradation of speech sounds by digital compression enhanced the evoked responses originating from the auditory cortex, whereas addition of stochastic noise did not modulate the cortical responses. Furthermore, it was shown that if the distortion was presented continuously in the background, the transient activity of auditory cortex was delayed. On the perceptual level, digital compression reduced the comprehensibility of speech more than additive stochastic noise. In addition, it was also demonstrated that prior knowledge of speech content enhanced the intelligibility of distorted speech substantially, and this perceptual change was associated with an increase in cortical activity within several regions adjacent to auditory cortex. In conclusion, the results of this thesis show that the auditory cortex is very sensitive to the acoustic features of the distortion, while at later processing stages, several cortical areas reflect the intelligibility of speech. These findings suggest that the auditory system rapidly adapts to the variability of the auditory environment, and can efficiently utilize previous knowledge of speech content in deciphering acoustically degraded speech signals.Puheen havaitseminen on useimmiten vaivatonta ja luotettavaa myös erittÀin huonoissa kuunteluolosuhteissa. Puheen ymmÀrrettÀvyys voi kuitenkin heikentyÀ ympÀristön hÀiriölÀhteiden lisÀksi myös silloin, kun puhesignaalin rakennetta muutetaan esimerkiksi pakkaamalla digitaalista ÀÀntÀ. TÀllainen hÀiriö voi heikentÀÀ ymmÀrrettÀvyyttÀ jopa ulkoisia hÀiriöitÀ voimakkaammin, koska kuulojÀrjestelmÀ ei pysty hyödyntÀmÀÀn ÀÀnilÀhteen ominaisuuksia, kuten ÀÀnen tulosuuntaa, hÀiriön erottelemisessa puheesta. Akustisten hÀiriöiden vaikutuksia puheen havaitsemiseen on tutkttu laajalti, mutta havaitsemiseen liittyvÀt aivomekanismit tunnetaan edelleen melko puutteelisesti etenkin tilanteissa, joissa itse puhesignaali on laadultaan heikentynyt. TÀmÀn vÀitöskirjan tavoitteena oli tutkia puheen havaitsemisen aivomekanismeja tilanteissa, joissa puhesignaali on vaikeammin ymmÀrrettÀvissÀ joko ulkoisen ÀÀnilÀhteen tai digitaalisen pakkauksen vuoksi. VÀitöskirjan neljÀssÀ osatutkimuksessa lyhyiden puheÀÀnien ja jatkuvan puheen ymmÀrrettÀvyyttÀ muokattiin joko digitaalisen pakkauksen kautta tai lisÀÀmÀllÀ puhesignaaliin satunnaiskohinaa. PuheÀrsykkeisiin liittyvÀÀ aivotoimintaa tutkittiin magnetoenkefalografia-mittauksilla. Tutkimuksissa havaittiin, ettÀ kuuloaivokuorella syntyneet herÀtevasteet voimistuivat, kun puheÀÀntÀ pakattiin digitaalisesti. Sen sijaan puheÀÀniin lisÀtty satunnaiskohina ei vaikuttanut herÀtevasteisiin. Edelleen, mikÀli puheÀÀnien taustalla esitettiin jatkuvaa hÀiriötÀ, kuuloaivokuoren aktivoituminen viivÀstyi hÀiriön intensiteetin kasvaessa. Kuuntelukokeissa havaittiin, ettÀ digitaalinen pakkaus heikentÀÀ puheÀÀnien ymmÀrrettÀvyyttÀ voimakkaammin kuin satunnaiskohina. LisÀksi osoitettiin, ettÀ aiempi tieto puheen sisÀllöstÀ paransi merkittÀvÀsti hÀiriöisen puheen ymmÀrrettÀvyyttÀ, mikÀ heijastui aivotoimintaan kuuloaivokuoren viereisillÀ aivoalueilla siten, ettÀ ymmÀrrettÀvÀ puhe aiheutti suuremman aktivaation kuin heikosti ymmÀrrettÀvÀ puhe. VÀitöskirjan tulokset osoittavat, ettÀ kuuloaivokuori on erittÀin herkkÀ puheÀÀnien akustisille hÀiriöille, ja myöhemmissÀ prosessoinnin vaiheissa useat kuuloaivokuoren viereiset aivoalueet heijastavat puheen ymmÀrrettÀvyyttÀ. Tulosten mukaan voi olettaa, ettÀ kuulojÀrjestelmÀ mukautuu nopeasti ÀÀniympÀristön vaihteluihin muun muassa hyödyntÀmÀllÀ aiempaa tietoa puheen sisÀllöstÀ tulkitessaan hÀiriöistÀ puhesignaalia
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