Démarches d’investigation en sciences et construction du savoir

National audienceDepuis plusieurs années, les démarches dites «d’investigation» sont mises en avant dans les programmes scolaires en mathématiques et en sciences expérimentales. Depuis septembre 2013, les lycéens arrivant dans l’enseignement supérieur ont été initiés à ces démarches, en particulier à l’école primaire et au collège. Lors du minicolloque «Enseignement» du congrès général de la SFP 2013, nous nous sommes centrés sur ce nouveau «profil» d’étudiant qui nécessite d’être connu des enseignants du supérieur, en particulier concernant les démarches scientifiques

A thousand-genome panel retraces the global spread and adaptation of a major fungal crop pathogen

Human activity impacts the evolutionary trajectories of many species worldwide. Global trade of agricultural goods contributes to the dispersal of pathogens reshaping their genetic makeup and providing opportunities for virulence gains. Understanding how pathogens surmount control strategies and cope with new climates is crucial to predicting the future impact of crop pathogens. Here, we address this by assembling a global thousand-genome panel of Zymoseptoria tritici, a major fungal pathogen of wheat reported in all production areas worldwide. We identify the global invasion routes and ongoing genetic exchange of the pathogen among wheat-growing regions. We find that the global expansion was accompanied by increased activity of transposable elements and weakened genomic defenses. Finally, we find significant standing variation for adaptation to new climates encountered during the global spread. Our work shows how large population genomic panels enable deep insights into the evolutionary trajectory of a major crop pathogen

Functional mechanisms underlying pleiotropic risk alleles at the 19p13.1 breast-ovarian cancer susceptibility locus

A locus at 19p13 is associated with breast cancer (BC) and ovarian cancer (OC) risk. Here we analyse 438 SNPs in this region in 46,451 BC and 15,438 OC cases, 15,252 BRCA1 mutation carriers and 73,444 controls and identify 13 candidate causal SNPs associated with serous OC (P=9.2 × 10-20), ER-negative BC (P=1.1 × 10-13), BRCA1-associated BC (P=7.7 × 10-16) and triple negative BC (P-diff=2 × 10-5). Genotype-gene expression associations are identified for candidate target genes ANKLE1 (P=2 × 10-3) and ABHD8 (P<2 × 10-3). Chromosome conformation capture identifies interactions between four candidate SNPs and ABHD8, and luciferase assays indicate six risk alleles increased transactivation of the ADHD8 promoter. Targeted deletion of a region containing risk SNP rs56069439 in a putative enhancer induces ANKLE1 downregulation; and mRNA stability assays indicate functional effects for an ANKLE1 3′-UTR SNP. Altogether, these data suggest that multiple SNPs at 19p13 regulate ABHD8 and perhaps ANKLE1 expression, and indicate common mechanisms underlying breast and ovarian cancer risk

The FANCM:p.Arg658* truncating variant is associated with risk of triple-negative breast cancer

Abstract: Breast cancer is a common disease partially caused by genetic risk factors. Germline pathogenic variants in DNA repair genes BRCA1, BRCA2, PALB2, ATM, and CHEK2 are associated with breast cancer risk. FANCM, which encodes for a DNA translocase, has been proposed as a breast cancer predisposition gene, with greater effects for the ER-negative and triple-negative breast cancer (TNBC) subtypes. We tested the three recurrent protein-truncating variants FANCM:p.Arg658*, p.Gln1701*, and p.Arg1931* for association with breast cancer risk in 67,112 cases, 53,766 controls, and 26,662 carriers of pathogenic variants of BRCA1 or BRCA2. These three variants were also studied functionally by measuring survival and chromosome fragility in FANCM−/− patient-derived immortalized fibroblasts treated with diepoxybutane or olaparib. We observed that FANCM:p.Arg658* was associated with increased risk of ER-negative disease and TNBC (OR = 2.44, P = 0.034 and OR = 3.79; P = 0.009, respectively). In a country-restricted analysis, we confirmed the associations detected for FANCM:p.Arg658* and found that also FANCM:p.Arg1931* was associated with ER-negative breast cancer risk (OR = 1.96; P = 0.006). The functional results indicated that all three variants were deleterious affecting cell survival and chromosome stability with FANCM:p.Arg658* causing more severe phenotypes. In conclusion, we confirmed that the two rare FANCM deleterious variants p.Arg658* and p.Arg1931* are risk factors for ER-negative and TNBC subtypes. Overall our data suggest that the effect of truncating variants on breast cancer risk may depend on their position in the gene. Cell sensitivity to olaparib exposure, identifies a possible therapeutic option to treat FANCM-associated tumors

Functional mechanisms underlying pleiotropic risk alleles at the 19p13.1 breast-ovarian cancer susceptibility locus

A locus at 19p13 is associated with breast cancer (BC) and ovarian cancer (OC) risk. Here we analyse 438 SNPs in this region in 46,451 BC and 15,438 OC cases, 15,252 BRCA1 mutation carriers and 73,444 controls and identify 13 candidate causal SNPs associated with serous OC (P = 9.2 x 10(-20)), ER-negative BC (P = 1.1 x 10(-13)), BRCA1-associated BC (P = 7.7 x 10(-16)) and triple negative BC (P-diff = 2 x 10(-5)). Genotype-gene expression associations are identified for candidate target genes ANKLE1 (P = 2 x 10(-3)) and ABHD8 (PPeer reviewe

L’enclos cultuel laténien des « Jardins familiaux » à Sin-le-Noble (Nord, France) : dépôts mixtes de monnaies d’or et d’orfèvrerie celtique

International audienceL’aménagement d’un quartier au lieu-dit Le Raquet, sur les communes de Douai, Lambres et Sin-le-Noble (Nord) a conduit à la fouille en2011/2012 par la Communauté d’agglomération du Douaisis – Direction de l’archéologie préventive, d’une superficie de 1,3 ha. À cette occasion fut découvert un enclos quadrangulaire d’environ 40 m de côté, partiellement détruit par l’érosion. Le fossé a livré différents dépôts qui permettent d’avancer une destination au moins partiellement cultuelle pour cet enclos. On y a en effet découvert la sépulture d’un individu en position contrainte ; trois (?) dépôts soigneusement mis en scène, associant des monnaies à des bijoux en or ; un vase complet contenant des résidus organiques (dépôt n° 4), et finalement un dépôt n° 5 constitué de dix pesons en terre cuite. Les dépôts ont été fouillés en laboratoire, et leur mise en scène complexe a pu être mise en évidence. Ils associent des monnaies – statères unifaces « ambiani » et quarts de statères « au bateau » – à des objets en or : dix statères, sept quarts de statères et un brassard en or (dépôt n°1) ; sept statères et quatre quarts de statères (dépôt n° 2) ; un statère et un anneau en or (dépôt n° 3). L’étude céramologique pointe vers une date se situant vers le milieu du Ier s. av. J.-C. Les différents contextes régionaux dans lesquels les monnaies apparaissent sont datables des années 50/40-30 av. J.-C. et sont dès lors postérieurs à la Guerre des Gaules. Le remblaiement du fossé est antérieur au règne d’Auguste