Voyage au Québec - 1er épisode

Au printemps 2001, la Section étude et recherche de l’ABF a organisé un voyage d’étude au Québec qui a donné lieu à plusieurs rapports, riches d’enseignements et de confrontations pour nos deux pays. Nous vous les présenterons au fil des numéros de BIBLIOthèque(s) et commençons ce feuilleton par la visite de trois bibliothèques publiques, commentée par Pascale Deligny et Catherine Ribet-Picard

Études des sculptures en marbre découvertes à Arles dans le Rhône : bilan des premières analyses

Les fouilles archéologiques subaquatiques menées dans le Rhône depuis 2007 ont renouvelé le faciès du matériel archéologique lié au dépotoir portuaire au profit d’un matériel urbain révélant des sculptures décoratives. Issues de contextes variés, privés, cultuels ou politiques, 67 pièces fragmentaires, de bronze, de calcaire ou de marbre, sont concernées et précisent notre connaissance de la rive droite du fleuve à Arles. Des investigations scientifiques ont permis des analyses technologiques et géologiques déterminant les carrières d’origines des marbres. À ce stade de la recherche, une prédominance de l’usage de marbres orientaux d’importation s’affirme pour la statuaire qui, dans certains cas pourrait être issues d’un atelier situé à Arles.The underwater archaeological excavations conducted in the Rhône river since 2007 changed the characteristics of the archaeological artefacts connected to the harbour dump in favor of urban material revealing ornamental sculptures. This material includes 67 more or less fragmentary parts, of bronze, limestone or marble, from varied, private, religious and political contexts, and refines our knowledge of the right bank of the river in Arles. Scientific investigations have led to the determination of quarry origins for the marble. At this stage of research, there is a predominance of imported Oriental marble used for statuary, which, in certain cases, could have been produced in a workshop in Arles

Estimation of additive and dominant variance of egg quality traits in pure-line layers

Improved performances are partly due to heterosis effects. One of the basis of heterosis is dominance, which cannot be inherited.However, it can be exploited to boost the total genetic merit of the animals. This has a special interest in avian selection schemeswhere commercial animals are crossbred. In this study, we have estimated additive and dominance genetic variances for severalegg quality traits in pure-line layers.Around 10,500 egg quality performances were used, collected from 1,148 female Rhode Island layers, phenotyped at 70 weeksold and genotyped using a 600K high density SNP chip. Five egg quality traits were analysed: egg weight (EW), egg shell color(ESC), egg shell strength (ESS), albumen height (AH) and egg shell shape (ESShape). Additive and dominance genetic varianceswere estimated via EM-REML with univariate models. That included an inbreeding coefficient and an additive and a dominancerandom effect. Dominance variance explained a small fraction of the phenotypic variance (between 2 to 4 % across all traits).However, it represented a relevant fraction of the total genetic variance for some of the traits (16%, 10%, 35%, 2.4% and 15% ofthe total genetic variance for EW, ESC, ESS, AH, ESShape, respectively).Further research will estimate additive and dominance genetic correlations between the traits to maximize the total genetic gainof these traits simultaneously. In addition, a genomic BLUP with dominance effects is envisaged for the joint analyses of purebredand crossbred performances, to evaluate the potential to generate superior crossbred performances

Interest of Genotyping-by-Sequencing technologies as an alternative to low density SNP chips for genomic selection in layer chicken

To reduce the cost of genomic selection, low density SNP chip can be used in combination with imputation for genotyping the selection candidates instead of using high density (HD) SNP chip. Concurrently, next-generation sequencing (NGS) techniques has been increasingly used in livestock species but remain expensive to be routinely used in selection. An alternative and costefficient solution is the Genotyping by Genome Reducing and Sequencing (GGRS) techniques to sequence only a fraction of the genome by using restriction enzymes. This approach was simulated from sequences of 1027 individuals in a pure layer line, using four enzymes (EcoRI, TaqI, AvaII and PstI). Imputation accuracy on HD genotypes was assessed as the mean correlation between true and imputed genotypes. Egg weight, egg shell color, egg shell strength and albumen height were evaluated with single-step GBLUP methodology. The impact of imputation errors on the genomic estimated breeding values (GEBV) was also investigated.AvaII or PstI led to the detection of more than 10K SNPs in common with the HD SNP chip resulting in imputation accuracy higher than 0.97. The impact of imputation errors on the ranking of the selection candidates was reduced with Spearman correlation (between GEBV calculated on true and imputed genotypes) higher than 0.97 for AvaII and PstI. Finally, the GGRS approach can be an interesting alternative to low density SNP chip for genomic selection. However, with real data, heterogeneity between individuals with missing data has to be taken into account

Letter from Sarah Forrer, Dayton, OH to Augusta Bruen, 1862 July 6

Use of data from crossbred animals for a genomic evaluation of pure line layer. XIth European symposium on poultry genetics (ESPG

Etude du déséquilibre de liaison dans des lignées de poules de types génétiques "ponte" et "chair"

International audienceLa structure du déséquilibre de liaison (DL) au sein des populations en sélection impacte fortement la précision obtenue lors des études de cartographie de QTL ou lors de l'évaluation génomique des reproducteurs. Chez les oiseaux, la structure hétérogène du génome nécessite de décrire précisément le DL pour optimiser la sélection. L'utilisation des puces SNP haute densité pour le génotypage des populations de volailles est une opportunité pour approfondir notre connaissance de la structure du DL de ces populations. L'objectif de cette étude est d'acquérir une connaissance haute résolution de la structure du DL au sein de populations de poules de types ponte et chair. Nous avons analysé les génotypes (puce 600 K Affymetrix® Axiom® HD SNP) de 1541 animaux issus de 3 populations. L'étendue et le niveau du DL ont été estimés par le r 2 moyen à distance physique donnée entre SNP. Cette étude met en évidence des différences importantes de structure du DL entre lignées et entre chromosomes. L'étendue et le niveau du DL sont plus importants dans les lignées de type ponte ou pour les macro-chromosomes et le chromosome Z. Ce niveau important de DL peut faciliter la détection de QTL sur ces chromosomes, mais peut également compliquer la localisation fine de polymorphismes causaux. A l'inverse, le faible niveau de DL observé sur les micro-chromosomes nécessite l'utilisation d'une forte densité de SNP pour détecter une association avec un phénotype, mais devrait permettre la cartographie fine d'un polymorphisme causal. Ces différences sont à prendre en considération pour définir une stratégie de génotypage économique et efficace pour la cartographie fine de QTL ou l'évaluation génomique. ABSTRACT A Linkage disequilibrium study in layers and broiler commercial chicken populations. Knowledge of the linkage disequilibrium (LD) pattern is useful in animal genetic studies as it underlies mapping studies and genomic selection. This is all the more important in birds given the heterogeneous structure of the avian karyotype. Recently, the availability of the high density 600 K Affymetrix® Axiom® HD SNP genotyping array allowed to assess an in-depth knowledge of the LD pattern in chicken genome. The aim of the present study was to assess a higher resolution of the LD pattern in chicken genome in layer and broiler lines. In this study, we analyzed genotypes of 1541 animals from layers and broiler commercial populations to characterize their LD pattern. LD was measured by the average r 2 value at a given physical distance between SNP. LD extended over a larger region for layer lines than for broiler line. Most differences between lines appeared at small interval distances (< 0.5Mb). LD extent and decay differed considerably between chromosomes categories. Average r 2 values were higher for Z chromosome than for macro, intermediates and micro-chromosomes. The extent of useful LD observed for autosomal chromosomes was at least tenfold longer for layer lines than for broiler. Finally, this study shed light on high LD for Z chromosome. The differences in LD pattern observed between chromosomes and chicken lines should be taken into account to define an economically efficient genotyping strategy

Resuming Training in High-Level Athletes After Mild COVID-19 Infection: A Multicenter Prospective Study (ASCCOVID-19)

BACKGROUND: There is a paucity of data on cardiovascular sequelae of asymptomatic/mildly symptomatic SARS-Cov-2 infections (COVID). OBJECTIVES: The aim of this prospective study was to characterize the cardiovascular sequelae of asymptomatic/mildly symptomatic COVID-19 among high/elite-level athletes. METHODS: 950 athletes (779 professional French National Rugby League (F-NRL) players; 171 student athletes) were included. SARS-Cov-2 testing was performed at inclusion, and F-NRL athletes were intensely followed-up for incident COVID-19. Athletes underwent ECG and biomarker profiling (D-Dimer, troponin, C-reactive protein). COVID(+) athletes underwent additional exercise testing, echocardiography and cardiac magnetic resonance imaging (CMR). RESULTS: 285/950 athletes (30.0%) had mild/asymptomatic COVID-19 [79 (8.3%) at inclusion (COVID(+)(prevalent)); 206 (28.3%) during follow-up (COVID(+)(incident))]. 2.6% COVID(+) athletes had abnormal ECGs, while 0.4% had an abnormal echocardiogram. During stress testing (following 7-day rest), COVID(+) athletes had a functional capacity of 12.8 ± 2.7 METS with only stress-induced premature ventricular ectopy in 10 (4.3%). Prevalence of CMR scar was comparable between COVID(+) athletes and controls [COVID(+) vs. COVID(-); 1/102 (1.0%) vs 1/28 (3.6%)]. During 289 ± 56 days follow-up, one athlete had ventricular tachycardia, with no obvious link with a SARS-CoV-2 infection. The proportion with troponin I and CRP values above the upper-limit threshold was comparable between pre- and post-infection (5.9% vs 5.9%, and 5.6% vs 8.7%, respectively). The proportion with D-Dimer values above the upper-limit threshold increased when comparing pre- and post-infection (7.9% vs 17.3%, P = 0.01). CONCLUSION: The absence of cardiac sequelae in pauci/asymptomatic COVID(+) athletes is reassuring and argues against the need for systematic cardiac assessment prior to resumption of training (clinicaltrials.gov; NCT04936503).L'Institut de Rythmologie et modélisation Cardiaqu

CNS-PNETs with C19MC amplification and/or LIN28 expression comprise a distinct histogenetic diagnostic and therapeutic entity

Amplification of the C19MC oncogenic miRNA cluster and high LIN28 expression has been linked to a distinctly aggressive group of cerebral CNS-PNETs (group 1 CNS-PNETs) arising in young children. In this study, we sought to evaluate the diagnostic specificity of C19MC and LIN28, and the clinical and biological spectra of C19MC amplified and/or LIN28+ CNS-PNETs. We interrogated 450 pediatric brain tumors using FISH and IHC analyses and demonstrate that C19MC alteration is restricted to a sub-group of CNS-PNETs with high LIN28 expression; however, LIN28 immunopositivity was not exclusive to CNS-PNETs but was also detected in a proportion of other malignant pediatric brain tumors including rhabdoid brain tumors and malignant gliomas. C19MC amplified/LIN28+ group 1 CNS-PNETs arose predominantly in children <4 years old; a majority arose in the cerebrum but 24 % (13/54) of tumors had extra-cerebral origins. Notably, group 1 CNS-PNETs encompassed several histologic classes including embryonal tumor with abundant neuropil and true rosettes (ETANTR), medulloepithelioma, ependymoblastoma and CNS-PNETs with variable differentiation. Strikingly, gene expression and methylation profiling analyses revealed a common molecular signature enriched for primitive neural features, high LIN28/LIN28B and DNMT3B expression for all group 1 CNS-PNETs regardless of location or tumor histology. Our collective findings suggest that current known histologic categories of CNS-PNETs which include ETANTRs, medulloepitheliomas, ependymoblastomas in various CNS locations, comprise a common molecular and diagnostic entity and identify inhibitors of the LIN28/let7/PI3K/mTOR axis and DNMT3B as promising therapeutics for this distinct histogenetic entity. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s00401-014-1291-1) contains supplementary material, which is available to authorized users

Reelin Controls Progenitor Cell Migration in the Healthy and Pathological Adult Mouse Brain

Understanding the signals that control migration of neural progenitor cells in the adult brain may provide new therapeutic opportunities. Reelin is best known for its role in regulating cell migration during brain development, but we now demonstrate a novel function for reelin in the injured adult brain. First, we show that Reelin is upregulated around lesions. Second, experimentally increasing Reelin expression levels in healthy mouse brain leads to a change in the migratory behavior of subventricular zone-derived progenitors, triggering them to leave the rostral migratory stream (RMS) to which they are normally restricted during their migration to the olfactory bulb. Third, we reveal that Reelin increases endogenous progenitor cell dispersal in periventricular structures independently of any chemoattraction but via cell detachment and chemokinetic action, and thereby potentiates spontaneous cell recruitment to demyelination lesions in the corpus callosum. Conversely, animals lacking Reelin signaling exhibit reduced endogenous progenitor recruitment at the lesion site. Altogether, these results demonstrate that beyond its known role during brain development, Reelin is a key player in post-lesional cell migration in the adult brain. Finally our findings provide proof of concept that allowing progenitors to escape from the RMS is a potential therapeutic approach to promote myelin repair