365 resultados para Genetic Algoritgm
Resumo:
In the early 1900s, the wolf (Canis lupus) was extirpated from France and Switzerland. There is growing evidence that the species is presently recolonizing these countries in the western Alps. By sequencing the mitochondrial DNA (mtDNA) control region of various samples mainly collected in the field (scats, hairs, regurgitates, blood or tissue; n = 292), we could (1) develop a non-invasive method enabling the unambiguous attribution of these samples to wolf, fox (Vulpes vulpes) or dog (Canis familiaris), among others; (2) demonstrate that Italian, French and Swiss wolves share the same mtDNA haplotype, a haplotype that has never been found in any other wolf population world-wide. Combined together, field and genetic data collected over 10 years corroborate the scenario of a natural expansion of wolves from the Italian source population. Furthermore, such a genetic approach is of conservation significance, since it has important consequences for management decisions. This first long-term report using non-invasive sampling demonstrates that long-distance dispersers are common, supporting the hypothesis that individuals may often attempt to colonize far from their native pack, even in the absence of suitable corridors across habitats characterized by intense human activities.
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Genome-wide studies in major depression have identified few replicated associations, potentially due to heterogeneity within the disorder. Several studies have suggested that age at onset (AAO) can distinguish sub-types of depression with specific heritable components. This paper investigates the role of AAO in the genetic susceptibility for depression using genome-wide association data on 2,746 cases and 1,594 screened controls from the RADIANT studies, with replication performed in 1,471 cases and 1,403 controls from two Munich studies. Three methods were used to analyze AAO: First a time-to-event analysis with controls censored, secondly comparing controls to case-subsets defined using AAO cut-offs, and lastly analyzing AAO as a quantitative trait. In the time-to-event analysis three SNPs reached suggestive significance (P < 5E-06), overlapping with the original case-control analysis of this study. In a case-control analysis using AAO thresholds, SNPs in 10 genomic regions showed suggestive association though again none reached genome-wide significance. Lastly, case-only analysis of AAO as a quantitative trait resulted in 5 SNPs reaching suggestive significance. Sex specific analysis was performed as a secondary analysis, yielding one SNP reaching genome-wide significance in early-onset males. No SNPs achieved significance in the replication study after correction for multiple testing. Analysis of AAO as a quantitative trait did suggest that, across all SNPs, common genetic variants explained a large proportion of the variance (51%, P = 0.04). This study provides the first focussed analysis of the genetic contribution to AAO in depression, and establishes a statistical framework that can be applied to a quantitative trait underlying any disorder. © 2012 Wiley Periodicals, Inc.
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OBJECTIVE: To establish the genetic basis of Landau-Kleffner syndrome (LKS) in a cohort of two discordant monozygotic (MZ) twin pairs and 11 isolated cases. METHODS: We used a multifaceted approach to identify genetic risk factors for LKS. Array comparative genomic hybridization (CGH) was performed using the Agilent 180K array. Whole genome methylation profiling was undertaken in the two discordant twin pairs, three isolated LKS cases, and 12 control samples using the Illumina 27K array. Exome sequencing was undertaken in 13 patients with LKS including two sets of discordant MZ twins. Data were analyzed with respect to novel and rare variants, overlapping genes, variants in reported epilepsy genes, and pathway enrichment. RESULTS: A variant (cG1553A) was found in a single patient in the GRIN2A gene, causing an arginine to histidine change at site 518, a predicted glutamate binding site. Following copy number variation (CNV), methylation, and exome sequencing analysis, no single candidate gene was identified to cause LKS in the remaining cohort. However, a number of interesting additional candidate variants were identified including variants in RELN, BSN, EPHB2, and NID2. SIGNIFICANCE: A single mutation was identified in the GRIN2A gene. This study has identified a number of additional candidate genes including RELN, BSN, EPHB2, and NID2. A PowerPoint slide summarizing this article is available for download in the Supporting Information section here.
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There are numerous genodermatoses and different types of transmission. Recent technological progress of molecular genetics allows to confirm or specify increasingly the clinical diagnosis and to better define the risk of recurrency. A close collaboration of dermatologists and geneticists has been established at CHUV since several years. By means of clinical examples we illustrate the organisation and procedures of this pluridisciplinary consultation which aims to optimize the clinical management of rare genetic diseases.
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The relative occurrence of genetic variants of human alpha 1-acid glycoprotein (AGP) in relation to changes in glycosylation was studied in sera of patients with burn injury, media of cytokine-treated primary cultures of human hepatocytes and Hep 3B cells, and sera of transgenic mice expressing the human AGP-A gene. It is concluded (i) that the glycosylation of AGP was not dependent on its genetic expression and (ii) that both the variants determined by the AGP-A gene as well as by the AGP-B/B' genes are increased after inflammation or treatment with interleukins 1 and 6.
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Urotensin-II controls ion/water homeostasis in fish and vascular tone in rodents. We hypothesised that common genetic variants in urotensin-II pathway genes are associated with human blood pressure or renal function. We performed family-based analysis of association between blood pressure, glomerular filtration and genes of the urotensin-II pathway (urotensin-II, urotensin-II related peptide, urotensin-II receptor) saturated with 28 tagging single nucleotide polymorphisms in 2024 individuals from 520 families; followed by an independent replication in 420 families and 7545 unrelated subjects. The expression studies of the urotensin-II pathway were carried out in 97 human kidneys. Phylogenetic evolutionary analysis was conducted in 17 vertebrate species. One single nucleotide polymorphism (rs531485 in urotensin-II gene) was associated with adjusted estimated glomerular filtration rate in the discovery cohort (p = 0.0005). It showed no association with estimated glomerular filtration rate in the combined replication resource of 8724 subjects from 6 populations. Expression of urotensin-II and its receptor showed strong linear correlation (r = 0.86, p<0.0001). There was no difference in renal expression of urotensin-II system between hypertensive and normotensive subjects. Evolutionary analysis revealed accumulation of mutations in urotensin-II since the divergence of primates and weaker conservation of urotensin-II receptor in primates than in lower vertebrates. Our data suggest that urotensin-II system genes are unlikely to play a major role in genetic control of human blood pressure or renal function. The signatures of evolutionary forces acting on urotensin-II system indicate that it may have evolved towards loss of function since the divergence of primates.
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Predicting progeny performance from parental genetic divergence can potentially enhance the efficiency of supportive breeding programmes and facilitate risk assessment. Yet, experimental testing of the effects of breeding distance on offspring performance remains rare, especially in wild populations of vertebrates. Recent studies have demonstrated that embryos of salmonid fish are sensitive indicators of additive genetic variance for viability traits. We therefore used gametes of wild brown trout (Salmo trutta) from five genetically distinct populations of a river catchment in Switzerland, and used a full factorial design to produce over 2,000 embryos in 100 different crosses with varying genetic distances (FST range 0.005-0.035). Customized egg capsules allowed recording the survival of individual embryos until hatching under natural field conditions. Our breeding design enabled us to evaluate the role of the environment, of genetic and nongenetic parental contributions, and of interactions between these factors, on embryo viability. We found that embryo survival was strongly affected by maternal environmental (i.e. non-genetic) effects and by the microenvironment, i.e. by the location within the gravel. However, embryo survival was not predicted by population divergence, parental allelic dissimilarity, or heterozygosity, neither in the field nor under laboratory conditions. Our findings suggest that the genetic effects of inter-population hybridization within a genetically differentiated meta-population can be minor in comparison to environmental effects.
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Acquired genomic aberrations have been shown to significantly impact survival in several hematologic malignancies. We analyzed the prognostic value of the most frequent chromosomal changes in a large series of patients with newly diagnosed symptomatic myeloma prospectively enrolled in homogeneous therapeutic trials. All the 1064 patients enrolled in the IFM99 trials conducted by the Intergroupe Francophone du Myélome benefited from an interphase fluorescence in situ hybridization analysis performed on purified bone marrow plasma cells. They were systematically screened for the following genomic aberrations: del(13), t(11;14), t(4;14), hyperdiploidy, MYC translocations, and del(17p). Chromosomal changes were observed in 90% of the patients. The del(13), t(11;14), t(4;14), hyperdiploidy, MYC translocations, and del(17p) were present in 48%, 21%, 14%, 39%, 13%, and 11% of the patients, respectively. After a median follow-up of 41 months, univariate statistical analyses revealed that del(13), t(4;14), nonhyperdiploidy, and del(17p) negatively impacted both the event-free survival and the overall survival, whereas t(11;14) and MYC translocations did not influence the prognosis. Multivariate analyses on 513 patients annotated for all the parameters showed that only t(4;14) and del(17p) retained prognostic value for both the event-free and overall survivals. When compared with the currently used International Staging System, this prognostic model compares favorably. In myeloma, the genomic aberrations t(4;14) and del(17p), together with beta2-microglobulin level, are important independent predictors of survival. These findings have implications for the design of risk-adapted treatment strategies.
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Wood ant species show differences in their social structure, especially in the level of polygyny (number of laying queens per nest) and polydomy (number of nest per colony), both within and between species. We demonstrate here for the first time that Formica lugubris displays two different social forms in close proximity in alpine unmanaged forests of the Swiss National Park. The genetic data (7 microsatellite loci) and field data indicate that one population is mostly monogynous to weakly polygynous (r = 0.438) and monodomous, the second one being polygynous (r = 0.113) and polydomous. Within this latter population new nests are founded by budding, leading to the observed high density of nests. These two different social structures, possibly being two expressions of a same continuum, could be explained by several ecological or environmental factors (e.g. habitat saturation, resource competition) and also historical effects.
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Protein electrophoresis was used to assess the phylogenetic relationships of populations of the phenotypically variable Asian house shrew Suncus murinus. These populations represent a sample of both commensal and wild forms. They were compared to another taxon, S. montanus, which was formerly considered conspecific with S. murinus. Suncus dayi was used as an outgroup in all phylogenetic reconstructions. Within the S. murinus lineage, the allozyme data show very low levels of genetic differentiation among both wild and commensal Southeast Asian and Japanese samples when compared to the Indian populations. This pattern is consistent with the classical hypothesis of a recent introduction by man in Eastern Asia. The higher genetic diversity found within S. murinus from India, as well as previous mitochondrial and karyological results suggest that this area is the probable centre of origin for the species. Although the lack of gene flow between S. murinus and S. montanus is clearly established in an area of sympatry in Southern India, one Asian house shrew sampled in Nepal was more closely related to S. montanus. This could either reflect the retention of an ancestral polymorphism, or result from a hybridization episode between S. murinus and S. montanus. Similar conclusions were also suggested in mitochondrial DNA studies dealing with animals sampled in the Northern parts of the Indian subcontinent. Clearly, further data on Suncus from this area are needed in order to assess these hypotheses. (C) 1995 The Linnean Society of London
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quantiNemo is an individual-based, genetically explicit stochastic simulation program. It was developed to investigate the effects of selection, mutation, recombination and drift on quantitative traits with varying architectures in structured populations connected by migration and located in a heterogeneous habitat. quantiNemo is highly flexible at various levels: population, selection, trait(s) architecture, genetic map for QTL and/or markers, environment, demography, mating system, etc. quantiNemo is coded in C++ using an object-oriented approach and runs on any computer platform. Availability: Executables for several platforms, user's manual, and source code are freely available under the GNU General Public License at http://www2.unil.ch/popgen/softwares/quantinemo.
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Le cytomégalovirus (CMV) est le pathogène viral le plus important après transplantation d'organe. Le risque de développer une maladie à CMV chez les patients transplantés dépend d'une combinaison de facteurs de l'hôte et de facteurs viraux. Par exemple, il est bien établi que le status sérologique à CMV du donneur et du receveur est un facteur de risque très important pour développer une maladie à CMV, notamment chez le sous-groupe de patients donneurs positifs / receveurs négatifs (D+/R-). Par contre, il n'est pas complètement élucidé si des polymorphismes viraux spécifiques peuvent influencer l'évolution en la réponse thérapeutique chez des patients avec une infection à CMV. Nous avons évalué le rôle des différents génotypes de la glycoprotéine Β (gB) du CMV sur l'évolution clinique et virologique de la maladie à CMV chez des patients transplantés d'organe sous traitement antiviral.¦Pour ce faire, nous avons étudié 239 patients transplantés d'organe inclus dans une étude multicentrique évaluant deux médicaments antiviraux utilisés comme traitement de la maladie à CMV. Le génotypage de la gB du CMV a été réalisé en utilisant une PCR quantitative en temps réel au début du traitement antiviral. Les polymorphismes de la gB du CMV permettent la discrimination de quatre génotypes distincts (gBl, gB2, gB3 et gB4). Nous avons défini une infection mixte comme la présence simultanée de plus d'un génotype chez un patient avec maladie à CMV.¦La prévalence des différents génotypes de la gB a été 26% pour la gBl, 10% pour la gB2, 10% pour la gB3, et 5% pour la gB4, alors que les infections mixtes étaient présentes dans 49% des cas. Les patients D+/R+ présentaient plus fréquemment une infection mixte que les patients D+/R- (40% vs 12%, ρ <0.001). Les patients avec une infection mixte présentaient une médiane de la charge virale à CMV plus élevée et un temps d'éradication virale plus long comparé à des patients avec une infection par un génotype unique (p=0.005 et p=0.026, respectivement). Dans un modèle multivarié, les infections mixtes étaient un prédicteur important de l'échec de l'éradication de virus au jour 21 du début du traitement antiviral (rapport de côtes entre l'infection mixte vs. infection par un génotype unique = 2.66, intervalle de confiance à 95%= 1.31 à 5.38, p= 0.007). Aucun effet du génotype gB sur le développement d'une récidive clinique ou virologique de l'infection à CMV a été observé.¦Ces résultats indiquent qu'aucun génotype spécifique de la gB ne semble conférer un avantage de virulence au CMV. Cependant, les infections mixtes avec plusieurs génotypes de la gB sont associées à une charge virale plus élevée et à un retard de l'éradication virale suite au traitement antiviral.
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Spondylocarpotarsal synostosis syndrome (SCT) (OMIM 272460), originally thought to be a failure of normal spine segmentation, is characterized by progressive fusion of vertebras and associates unsegmented bars, scoliosis, short stature, carpal and tarsal synostosis. Cleft palate, sensorineural or mixed hearing loss, joint limitation, clinodactyly, and dental enamel hypoplasia are variable manifestations. Twenty-five patients have been reported. Thirteen affected individuals were siblings from six families and four of these families were consanguineous. In four of those families, Krakow et al. [Krakow et al. (2004) Nat Genet 36:405-410] found homozygosity or compound heterozygosity for mutations in the gene encoding FLNB. This confirmed autosomal recessive inheritance of the disorder. We report on two new patients (a mother and her son) representing the first case of autosomal dominant inheritance. These patients met the clinical and radiological criteria for SCT and did not present any features which could exclude this diagnosis. Molecular analysis failed to identify mutations in NOG and FLNB. SCT is therefore, genetically heterogeneous. Both dominant and autosomal recessive forms of inheritance should be considered during genetic counseling.
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A genome-wide association study (GWAS) of educational attainment was conducted in a discovery sample of 101,069 individuals and a replication sample of 25,490. Three independent single-nucleotide polymorphisms (SNPs) are genome-wide significant (rs9320913, rs11584700, rs4851266), and all three replicate. Estimated effects sizes are small (coefficient of determination R(2) ≈ 0.02%), approximately 1 month of schooling per allele. A linear polygenic score from all measured SNPs accounts for ≈2% of the variance in both educational attainment and cognitive function. Genes in the region of the loci have previously been associated with health, cognitive, and central nervous system phenotypes, and bioinformatics analyses suggest the involvement of the anterior caudate nucleus. These findings provide promising candidate SNPs for follow-up work, and our effect size estimates can anchor power analyses in social-science genetics.