1,622 research outputs found

    The genome sequencing of an albino Western lowland gorilla reveals inbreeding in the wild

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    Background The only known albino gorilla, named Snowflake, was a male wild born individual from Equatorial Guinea who lived at the Barcelona Zoo for almost 40 years. He was diagnosed with non-syndromic oculocutaneous albinism, i.e. white hair, light eyes, pink skin, photophobia and reduced visual acuity. Despite previous efforts to explain the genetic cause, this is still unknown. Here, we study the genetic cause of his albinism and making use of whole genome sequencing data we find a higher inbreeding coefficient compared to other gorillas. Results We successfully identified the causal genetic variant for Snowflake¿s albinism, a non-synonymous single nucleotide variant located in a transmembrane region of SLC45A2. This transporter is known to be involved in oculocutaneous albinism type 4 (OCA4) in humans. We provide experimental evidence that shows that this amino acid replacement alters the membrane spanning capability of this transmembrane region. Finally, we provide a comprehensive study of genome-wide patterns of autozygogosity revealing that Snowflake¿s parents were related, being this the first report of inbreeding in a wild born Western lowland gorilla. Conclusions In this study we demonstrate how the use of whole genome sequencing can be extended to link genotype and phenotype in non-model organisms and it can be a powerful tool in conservation genetics (e.g., inbreeding and genetic diversity) with the expected decrease in sequencing cost. Keywords: Gorilla; Albinism; Inbreeding; Genome; Conservatio

    Genome-Wide Association Study of the Modified Stumvoll Insulin Sensitivity Index Identifies BCL2 and FAM19A2 as Novel Insulin Sensitivity Loci

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    Genome-wide association studies (GWAS) have found few common variants that influence fasting measures of insulin sensitivity. We hypothesized that a GWAS of an integrated assessment of fasting and dynamic measures of insulin sensitivity would detect novel common variants. We performed a GWAS of the modified Stumvoll Insulin Sensitivity Index (ISI) within the Meta-Analyses of Glucose and Insulin-Related Traits Consortium. Discovery for genetic association was performed in 16,753 individuals, and replication was attempted for the 23 most significant novel loci in 13,354 independent individuals. Association with ISI was tested in models adjusted for age, sex, and BMI and in a model analyzing the combined influence of the genotype effect adjusted for BMI and the interaction effect between the genotype and BMI on ISI (model 3). In model 3, three variants reached genome-wide significance: Rs13422522 (NYAP2; P = 8.87 × 10-11), rs12454712 (BCL2; P = 2.7 × 10-8), and rs10506418 (FAM19A2; P = 1.9 × 10-8). The association at NYAP2 was eliminated by conditioning on the known IRS1 insulin sensitivity locus; the BCL2 and FAM19A2 associations were independent of known cardiometabolic loci. In conclusion, we identified two novel loci and replicated known variants associated with insulin sensitivity. Further studies are needed to clarify the causal variant and function at the BCL2 and FAM19A2 loci

    Unsupervised protein embeddings outperform hand-crafted sequence and structure features at predicting molecular function

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    Motivation: Protein function prediction is a difficult bioinformatics problem. Many recent methods use deep neural networks to learn complex sequence representations and predict function from these. Deep supervised models require a lot of labeled training data which are not available for this task. However, a very large amount of protein sequences without functional labels is available.Results: We applied an existing deep sequence model that had been pretrained in an unsupervised setting on the supervised task of protein molecular function prediction. We found that this complex feature representation is effective for this task, outperforming hand-crafted features such as one-hot encoding of amino acids, k-mer counts, secondary structure and backbone angles. Also, it partly negates the need for complex prediction models, as a two-layer perceptron was enough to achieve competitive performance in the third Critical Assessment of Functional Annotation benchmark. We also show that combining this sequence representation with protein 3D structure information does not lead to performance improvement, hinting that 3D structure is also potentially learned during the unsupervised pretraining

    Nucleic acid amplification tests in the diagnosis of tuberculous pleuritis: a systematic review and meta-analysis

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    BACKGROUND: Conventional tests for tuberculous pleuritis have several limitations. A variety of new, rapid tests such as nucleic acid amplification tests – including polymerase chain reaction – have been evaluated in recent times. We conducted a systematic review to determine the accuracy of nucleic acid amplification (NAA) tests in the diagnosis of tuberculous pleuritis. METHODS: A systematic review and meta-analysis of 38 English and Spanish articles (with 40 studies), identified via searches of six electronic databases, hand searching of selected journals, and contact with authors, experts, and test manufacturers. Sensitivity, specificity, and other measures of accuracy were pooled using random effects models. Summary receiver operating characteristic curves were used to summarize overall test performance. Heterogeneity in study results was formally explored using subgroup analyses. RESULTS: Of the 40 studies included, 26 used in-house ("home-brew") tests, and 14 used commercial tests. Commercial tests had a low overall sensitivity (0.62; 95% confidence interval [CI] 0.43, 0.77), and high specificity (0.98; 95% CI 0.96, 0.98). The positive and negative likelihood ratios for commercial tests were 25.4 (95% CI 16.2, 40.0) and 0.40 (95% CI 0.24, 0.67), respectively. All commercial tests had consistently high specificity estimates; the sensitivity estimates, however, were heterogeneous across studies. With the in-house tests, both sensitivity and specificity estimates were significantly heterogeneous. Clinically meaningful summary estimates could not be determined for in-house tests. CONCLUSIONS: Our results suggest that commercial NAA tests may have a potential role in confirming (ruling in) tuberculous pleuritis. However, these tests have low and variable sensitivity and, therefore, may not be useful in excluding (ruling out) the disease. NAA test results, therefore, cannot replace conventional tests; they need to be interpreted in parallel with clinical findings and results of conventional tests. The accuracy of in-house nucleic acid amplification tests is poorly defined because of heterogeneity in study results. The clinical applicability of in-house NAA tests remains unclear

    A measurement of ∆Γs

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    Using a dataset corresponding to 9 fb−1 of integrated luminosity collected with the LHCb detector between 2011 and 2018 in proton-proton collisions, the decay-time distributions of the decay modes Bs 0→J/ψη′ and Bs 0→J/ψπ+π− are studied. The decay-width difference between the light and heavy mass eigenstates of the Bs 0 meson is measured to be ∆Γs = 0.087 ± 0.012 ± 0.009 ps−1, where the first uncertainty is statistical and the second systematic

    Observation of the decays B(s)0Ds1(2536)K±B_{(s)}^{0}\to D_{s1}(2536)^{\mp}K^{\pm}

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    This paper reports the observation of the decays B(s)0Ds1(2536)K±B_{(s)}^{0}\to D_{s1}(2536)^{\mp}K^{\pm} using proton-proton collision data collected by the LHCb experiment, corresponding to an integrated luminosity of 9fb19\,\mathrm{fb}^{-1}. The branching fractions of these decays are measured relative to the normalisation channel B0D0K+KB^{0}\to \overline{D}^{0}K^{+}K^{-}. The Ds1(2536)D_{s1}(2536)^{-} meson is reconstructed in the D(2007)0K\overline{D}^{*}(2007)^{0}K^{-} decay channel and the products of branching fractions are measured to be B(Bs0Ds1(2536)K±)×B(Ds1(2536)D(2007)0K)=(2.49±0.11±0.12±0.25±0.06)×105,\mathcal{B}(B_{s}^{0}\to D_{s1}(2536)^{\mp}K^{\pm})\times\mathcal{B}(D_{s1}(2536)^{-}\to\overline{D}^{*}(2007)^{0}K^{-})=(2.49\pm0.11\pm0.12\pm0.25\pm0.06)\times 10^{-5}, B(B0Ds1(2536)K±)×B(Ds1(2536)D(2007)0K)=(0.510±0.021±0.036±0.050)×105.\mathcal{B}(B^{0}\to D_{s1}(2536)^{\mp}K^{\pm})\times\mathcal{B}(D_{s1}(2536)^{-}\to\overline{D}^{*}(2007)^{0}K^{-}) = (0.510\pm0.021\pm0.036\pm0.050)\times 10^{-5}. The first uncertainty is statistical, the second systematic, and the third arises from the uncertainty of the branching fraction of the B0D0K+KB^{0}\to \overline{D}^{0}K^{+}K^{-} normalisation channel. The last uncertainty in the Bs0B_{s}^{0} result is due to the limited knowledge of the fragmentation fraction ratio, fs/fdf_{s}/f_{d}. The significance for the Bs0B_{s}^{0} and B0B^{0} signals is larger than 10σ10\,\sigma. The ratio of the helicity amplitudes which governs the angular distribution of the Ds1(2536)D(2007)0KD_{s1}(2536)^{-}\to\overline{D}^{*}(2007)^{0}K^{-} decay is determined from the data. The ratio of the SS- and DD-wave amplitudes is found to be 1.11±0.15±0.061.11\pm0.15\pm 0.06 and its phase 0.70±0.09±0.040.70\pm0.09\pm 0.04 rad, where the first uncertainty is statistical and the second systematic.Comment: All figures and tables, along with machine-readable versions and any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2023-014.html (LHCb public pages

    Observation of strangeness enhancement with charmed mesons in high-multiplicity pPbp\mathrm{Pb} collisions at sNN=8.16\sqrt {s_{\mathrm{NN}}}=8.16\,TeV

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    The production of prompt Ds+D^+_{s} and D+D^+ mesons is measured by the LHCb experiment in proton-lead (pPbp\mathrm{Pb}) collisions in both the forward (1.5<y<4.01.5<y^*<4.0) and backward (5.0<y<2.5-5.0<y^*<-2.5) rapidity regions at a nucleon-nucleon center-of-mass energy of sNN=8.16\sqrt {s_{\mathrm{NN}}}=8.16\,TeV. The nuclear modification factors of both Ds+D^+_{s} and D+D^+ mesons are determined as a function of transverse momentum, pTp_{\mathrm{T}}, and rapidity. In addition, the Ds+D^+_{s} to D+D^+ cross-section ratio is measured as a function of the charged particle multiplicity in the event. An enhanced Ds+D^+_{s} to D+D^+ production in high-multiplicity events is observed for the whole measured pTp_{\mathrm{T}} range, in particular at low pTp_{\mathrm{T}} and backward rapidity, where the significance exceeds six standard deviations. This constitutes the first observation of strangeness enhancement in charm quark hadronization in high-multiplicity pPbp\mathrm{Pb} collisions. The results are also qualitatively consistent with the presence of quark coalescence as an additional charm quark hadronization mechanism in high-multiplicity proton-lead collisions.Comment: All figures and tables, along with machine-readable versions and any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2023-021.html (LHCb public pages

    A measurement of ΔΓs\Delta \Gamma_{s}

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    Using a dataset corresponding to 9 fb19~\mathrm{fb}^{-1} of integrated luminosity collected with the LHCb detector between 2011 and 2018 in proton-proton collisions, the decay-time distributions of the decay modes Bs0J/ψηB_s^0 \rightarrow J/\psi \eta' and Bs0J/ψπ+πB_s^0 \rightarrow J/\psi \pi^{+} \pi^{-} are studied. The decay-width difference between the light and heavy mass eigenstates of the Bs0B_s^0 meson is measured to be ΔΓs=0.087±0.012±0.009ps1\Delta \Gamma_s = 0.087 \pm 0.012 \pm 0.009 \, \mathrm{ps}^{-1}, where the first uncertainty is statistical and the second systematic.Comment: All figures and tables, along with machine-readable versions and any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2023-025.htm

    Momentum scale calibration of the LHCb spectrometer

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    For accurate determination of particle masses accurate knowledge of the momentum scale of the detectors is crucial. The procedure used to calibrate the momentum scale of the LHCb spectrometer is described and illustrated using the performance obtained with an integrated luminosity of 1.6 fb^−1 collected during 2016 in pp running. The procedure uses large samples of J/ψ → μ+ μ- and B+ → J/ψ K+ decays and leads to a relative accuracy of 3 × 10^−4 on the momentum scale

    Measurements of the branching fraction ratio B(ϕμ+μ)/B(ϕe+e)\cal{B}(\phi \to \mu^+\mu^-)/\cal{B}(\phi \to e^+e^-) with charm meson decays

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    Measurements of the branching fraction ratio B(ϕμ+μ)/B(ϕe+e){\cal{B}(\phi \to \mu^+ \mu^-)/\cal{B}(\phi\to e^+e^-)} with Ds+π+ϕ{D_{s}^{+} \to \pi^{+} \phi} and D+π+ϕ{D^{+} \to \pi^{+} \phi} decays, denoted RϕπsR^{s}_{\phi \pi} and RϕπdR^{d}_{\phi \pi}, are presented. The analysis is performed using a dataset corresponding to an integrated luminosity of 5.4fb1\,\rm{fb}^{-1} of pppp collision data collected with the LHCb experiment. The branching fractions are normalised with respect to the B+K+J/ψ(e+e){B^{+} \to K^{+} J/\psi(\to e^+e^-)} and B+K+J/ψ(μ+μ){B^{+} \to K^{+} J/\psi(\to \mu^+\mu^-)} decay modes. The combination of the results yields Rϕπ=1.022±0.012(stat)±0.048(syst). R_{\phi \pi} = 1.022 \pm 0.012 \,({\rm stat}) \, \pm 0.048 \,({\rm syst}). The result is compatible with previous measurements of the ϕ+\phi \to \ell^{+}\ell^{-} branching fractions and predictions based on the Standard Model.Comment: All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2023-038.html (LHCb public pages
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