| 351. |
- Blanco-Pastor, José Luis, et al.
(författare)
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Bees explain floral variation in a recent radiation of Linaria
- 2015
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Ingår i: Journal of Evolutionary Biology. - : Wiley. - 1420-9101 .- 1010-061X. ; 28:4, s. 851-863
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Tidskriftsartikel (refereegranskat)abstract
- The role of pollinators in floral divergence has long attracted the attention of evolutionary biologists. Although abundant studies have reported the effect of pollinators on flower-shape variation and plant speciation, the influence of pollinators on plant species differentiation during rapid radiations and the specific consequences of shifts among similar pollinators are not well understood. Here, we evaluate the association between pollinators and floral morphology in a closely related and recently diversifying clade of Linaria species (sect. Supinae subsect. Supinae). Our approach combined pollinator observations, functional floral morphometric measures and phylogenetic comparative analyses. The fauna visiting Linaria species was determined by extensive surveys and categorized by a modularity algorithm, and the size and shape of flowers were analysed by means of standard and geometric morphometric measures. Standard measures failed to find relationships between the sizes of representative pollinators and flowers. However, discriminant function analyses of geometric morphometric data revealed that pollination niches are finer predictors of flower morphologies in Linaria if compared with phylogenetic relationships. Species with the most restrictive flowers displayed the most slender spurs and were pollinated by bees with larger proboscides. These restrictive flower shapes likely appeared more than once during the evolutionary history of the study group. We show that floral variation can be driven by shifts between pollinators that have been traditionally included in a single functional group, and discuss the consequences of such transitions for plant species differentiation during rapid radiations. © 2015 European Society For Evolutionary Biology.
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| 352. |
- Blanco-Pastor, José Luis, et al.
(författare)
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Evolutionary networks from RADseq loci point to hybrid origins of Medicago carstiensis and Medicago cretacea
- 2019
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Ingår i: American Journal of Botany. - : Wiley. - 0002-9122 .- 1537-2197. ; 106:9, s. 1219-1228
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Tidskriftsartikel (refereegranskat)abstract
- Premise Although hybridization has played an important role in the evolution of many plant species, phylogenetic reconstructions that include hybridizing lineages have been historically constrained by the available models and data. Restriction-site-associated DNA sequencing (RADseq) has been a popular sequencing technique for the reconstruction of hybridization in the next-generation sequencing era. However, the utility of RADseq for the reconstruction of complex evolutionary networks has not been thoroughly investigated. Conflicting phylogenetic relationships in the genus Medicago have been mainly attributed to hybridization, but the specific hybrid origins of taxa have not been yet clarified. Methods We obtained new molecular data from diploid species of Medicago section Medicago using single-digest RADseq to reconstruct evolutionary networks from gene trees, an approach that is computationally tractable with data sets that include several species and complex hybridization patterns. Results Our analyses revealed that assembly filters to exclusively select a small set of loci with high phylogenetic information led to the most-divergent network topologies. Conversely, alternative clustering thresholds or filters on the number of samples per locus had a lower impact on networks. A strong hybridization signal was detected for M. carstiensis and M. cretacea, while signals were less clear for M. rugosa, M. rhodopea, M. suffruticosa, M. marina, M. scutellata, and M. sativa. Conclusions Complex network reconstructions from RADseq gene trees were not robust under variations of the assembly parameters and filters. But when the most-divergent networks were discarded, all remaining analyses consistently supported a hybrid origin for M. carstiensis and M. cretacea.
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| 353. |
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| 354. |
- Calvo, Patricia A, et al.
(författare)
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Motif WFYY of human PrimPol is crucial to stabilize the incoming 3'-nucleotide during replication fork restart
- 2021
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Ingår i: Nucleic Acids Research. - : Oxford University Press. - 0305-1048 .- 1362-4962. ; 49:14, s. 8199-8213
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Tidskriftsartikel (refereegranskat)abstract
- PrimPol is the second primase in human cells, the first with the ability to start DNA chains with dNTPs. PrimPol contributes to DNA damage tolerance by restarting DNA synthesis beyond stalling lesions, acting as a TLS primase. Multiple alignment of eukaryotic PrimPols allowed us to identify a highly conserved motif, WxxY near the invariant motif A, which contains two active site metal ligands in all members of the archeo-eukaryotic primase (AEP) superfamily. In vivo and in vitro analysis of single variants of the WFYY motif of human PrimPol demonstrated that the invariant Trp87 and Tyr90 residues are essential for both primase and polymerase activities, mainly due to their crucial role in binding incoming nucleotides. Accordingly, the human variant F88L, altering the WFYY motif, displayed reduced binding of incoming nucleotides, affecting its primase/polymerase activities especially during TLS reactions on UV-damaged DNA. Conversely, the Y89D mutation initially associated with High Myopia did not affect the ability to rescue stalled replication forks in human cells. Collectively, our data suggest that the WFYY motif has a fundamental role in stabilizing the incoming 3'-nucleotide, an essential requisite for both its primase and TLS abilities during replication fork restart.
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| 355. |
- Cantat-Gaudin, T., et al.
(författare)
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The Gaia-ESO Survey: Stellar content and elemental abundances in the massive cluster NGC 6705
- 2014
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Ingår i: Astronomy & Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 569
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Tidskriftsartikel (refereegranskat)abstract
- Context. Chemically inhomogeneous populations are observed in most globular clusters, but not in open clusters. Cluster mass seems to play a key role in the existence of multiple populations. Aims. Studying the chemical homogeneity of the most massive open clusters is needed to better understand the mechanism of their formation and determine the mass limit under which clusters cannot host multiple populations. Here we studied NGC 6705, which is a young and massive open cluster located towards the inner region of the Milky Way. This cluster is located inside the solar circle. This makes it an important tracer of the inner disk abundance gradient. Methods. This study makes use of BVI and ri photometry and comparisons with theoretical isochrones to derive the age of NGC 6705. We study the density profile of the cluster and the mass function to infer the cluster mass. Based on abundances of the chemical elements distributed in the first internal data release of the Gaia-ESO Survey, we study elemental ratios and the chemical homogeneity of the red clump stars. Radial velocities enable us to study the rotation and internal kinematics of the cluster. Results. The estimated ages range from 250 to 316 Myr, depending on the adopted stellar model. Luminosity profiles and mass functions show strong signs of mass segregation. We derive the mass of the cluster from its luminosity function and from the kinematics, finding values between 3700 M-circle dot and 11 000 M-circle dot. After selecting the cluster members from their radial velocities, we obtain a metallicity of [Fe/H] = 0.10 +/- 0.06 based on 21 candidate members. Moreover, NGC 6705 shows no sign of the typical correlations or anti-correlations between Al, Mg, Si, and Na, which are expected in multiple populations. This is consistent with our cluster mass estimate, which is lower than the required mass limit proposed in the literature to develop multiple populations.
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| 356. |
- Carton, C., et al.
(författare)
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ERN GENTURIS tumour surveillance guidelines for individuals with neurofibromatosis type 1
- 2023
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Ingår i: Eclinicalmedicine. - : Elsevier BV. - 2589-5370. ; 56
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Tidskriftsartikel (refereegranskat)abstract
- Background Neurofibromatosis type 1 (NF1) is a multisystem genetic disorder, predisposing development of benign and malignant tumours. Given the oncogenic potential, long-term surveillance is important in patients with NF1. Proposals for NF1 care and its specific manifestations have been developed, but lack integration within routine care. This guideline aims to assimilate available information on NF1 associated tumours (based on evidence and/ or expert opinion) to assist healthcare professionals in undertaking tumour surveillance of NF1 individuals.Methods By comprehensive literature review, performed March 18th 2020, guidelines were developed by a NF1 expert group and patient representatives, conversant with clinical care of the wide NF1 disease spectrum. We used a modified Delphi procedure to overcome issues of variability in recommendations for specific (national) health care settings, and to deal with recommendations based on indirect (scarce) evidence.Findings We defined proposals for personalised and targeted tumour management in NF1, ensuring appropriate care for those in need, whilst reducing unnecessary intervention. We also incorporated the tumour-related psychosocial and quality of life impact of NF1. Interpretation The guideline reflects the current care for NF1 in Europe. They are not meant to be prescriptive and may be adjusted to local available resources at the treating centre, both within and outside EU countries.Funding This guideline has been supported by the European Reference Network on Genetic Tumour Risk Syndromes (ERN GENTURIS). ERN GENTURIS is funded by the European Union. DGE is supported by the Manchester NIHR Biomedical Research Centre (IS-BRC-1215-20007). 2023;56: Published January https://doi.org/10. 1016/j.eclinm.2022. 101818
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| 357. |
- Casali, G., et al.
(författare)
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The Gaia-ESO survey : the non-universality of the age-chemical-clocks-metallicity relations in the Galactic disc
- 2020
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 639
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Tidskriftsartikel (refereegranskat)abstract
- Context. In the era of large spectroscopic surveys, massive databases of high-quality spectra coupled with the products of the Gaia satellite provide tools to outline a new picture of our Galaxy. In this framework, an important piece of information is provided by our ability to infer stellar ages, and consequently to sketch a Galactic timeline.Aims. We aim to provide empirical relations between stellar ages and abundance ratios for a sample of stars with very similar stellar parameters to those of the Sun, namely the so-called solar-like stars. We investigate the dependence on metallicity, and we apply our relations to independent samples, that is, the Gaia-ESO samples of open clusters and of field stars.Methods. We analyse high-resolution and high-signal-to-noise-ratio HARPS spectra of a sample of solar-like stars to obtain precise determinations of their atmospheric parameters and abundances for 25 elements and/or ions belonging to the main nucleosynthesis channels through differential spectral analysis, and of their ages through isochrone fitting.Results. We investigate the relations between stellar ages and several abundance ratios. For the abundance ratios with a steeper dependence on age, we perform multivariate linear regressions, in which we include the dependence on metallicity, [Fe/H]. We apply our best relations to a sample of open clusters located from the inner to the outer regions of the Galactic disc. Using our relations, we are able to recover the literature ages only for clusters located at R-GC > 7 kpc. The values that we obtain for the ages of the inner-disc clusters are much greater than the literature ones. In these clusters, the content of neutron capture elements, such as Y and Zr, is indeed lower than expected from chemical evolution models, and consequently their [Y/Mg] and [Y/Al] are lower than in clusters of the same age located in the solar neighbourhood. With our chemical evolution model and a set of empirical yields, we suggest that a strong dependence on the star formation history and metallicity-dependent stellar yields of s-process elements can substantially modify the slope of the [s/alpha]-[Fe/H]-age relation in different regions of the Galaxy.Conclusions. Our results point towards a non-universal relation [s/alpha]-[Fe/H]-age, indicating the existence of relations with different slopes and intercepts at different Galactocentric distances or for different star formation histories. Therefore, relations between ages and abundance ratios obtained from samples of stars located in a limited region of the Galaxy cannot be translated into general relations valid for the whole disc. A better understanding of the s-process at high metallicity is necessary to fully understand the origin of these variations.
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| 358. |
- Cenit, MC, et al.
(författare)
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Influence of the IL6 gene in susceptibility to systemic sclerosis
- 2012
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Ingår i: The Journal of rheumatology. - : The Journal of Rheumatology. - 0315-162X .- 1499-2752. ; 39:12, s. 2294-2302
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Tidskriftsartikel (refereegranskat)abstract
- Systemic sclerosis (SSc) is a genetically complex autoimmune disease; the genetic component has not been fully defined. Interleukin 6 (IL-6) plays a crucial role in immunity and fibrosis, both key aspects of SSc. We investigated the influence of IL6 gene in the susceptibility and phenotype expression of SSc.Methods.We performed a large metaanalysis including a total of 2749 cases and 3189 controls from 6 white populations (Germany, The Netherlands, Norway, Spain, Sweden, and United Kingdom). Three IL6 single-nucleotide polymorphisms (SNP; rs2069827, rs1800795, and rs2069840) were selected by SNP tagging and genotyped using TaqMan® allele discrimination technology.Results.Individual SNP metaanalysis showed no evidence of association of the 3 IL6 genetic variants with the global disease. Phenotype analyses revealed a significant association between the minor allele of rs2069840 and the limited cutaneous SSc clinical form (Bonferroni p = 0.036, OR 1.14, 95% CI 1.04–1.25). A trend of association between the minor allele of the rs1800795 and the diffuse cutaneous SSc clinical form was also evident (Bonferroni p = 0.072, OR 0.86, 95% CI 0.77–0.96). In the IL6 allelic combination analyses, the GGC allelic combination rs2069827-rs1800795-rs2069840 showed an association with overall SSc (Bonferroni p = 0.016, OR 1.13, 95% CI 1.04–1.23).Conclusion.Our results suggest that the IL6 gene may influence the development of SSc and its progression.
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| 359. |
- Clark, Andrew G., et al.
(författare)
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Evolution of genes and genomes on the Drosophila phylogeny
- 2007
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 450:7167, s. 203-218
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Tidskriftsartikel (refereegranskat)abstract
- Comparative analysis of multiple genomes in a phylogenetic framework dramatically improves the precision and sensitivity of evolutionary inference, producing more robust results than single-genome analyses can provide. The genomes of 12 Drosophila species, ten of which are presented here for the first time (sechellia, simulans, yakuba, erecta, ananassae, persimilis, willistoni, mojavensis, virilis and grimshawi), illustrate how rates and patterns of sequence divergence across taxa can illuminate evolutionary processes on a genomic scale. These genome sequences augment the formidable genetic tools that have made Drosophila melanogaster a pre-eminent model for animal genetics, and will further catalyse fundamental research on mechanisms of development, cell biology, genetics, disease, neurobiology, behaviour, physiology and evolution. Despite remarkable similarities among these Drosophila species, we identified many putatively non-neutral changes in protein-coding genes, non-coding RNA genes, and cis-regulatory regions. These may prove to underlie differences in the ecology and behaviour of these diverse species.
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| 360. |
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