996 resultados para new allele


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Using allozymes and mtDNA sequences from the cytochrome b gene, we report that the brown kiwi has the highest levels of genetic structuring observed in birds. Moreover, the mtDNA sequences are, with two minor exceptions, diagnostic genetic markers for each population investigated, even though they are among the more slowly evolving coding regions in this genome. A major unexpected finding was the concordant split in molecular phylogenies between brown kiwis in the southern South Island and elsewhere in New Zealand. This basic phylogeographic boundary halfway down the South Island coincides with a fixed allele difference in the Hb nuclear locus and strongly suggests that two morphologically cryptic species are currently merged under one polytypic species. This is another striking example of how molecular genetic assays can detect phylogenetic discontinuities that are not reflected in traditional morphologically based taxonomies. However, reanalysis of the morphological characters by using phylogenetic methods revealed that the reason for this discordance is that most are primitive and thus are phylogenetically uninformative. Shared-derived morphological characters support the same relationships evident in the molecular phylogenies and, in concert with the molecular data, suggest that as brown kiwis colonized northward from the southern South Island, they retained many primitive characters that confounded earlier systematists. Strong subdivided population structure and cryptic species in brown kiwis seem to have evolved relatively recently as a consequence of Pleistocene range disjunctions, low dispersal power, and genetic drift in small populations.

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Mutations in the Plasmodium falciparum chloroquine resistance transporter (pfcrt) gene were examined to assess their associations with chloroquine resistance in clinical samples from Armopa (Papua) and Papua New Guinea. In Papua, two of the five pfcrt haplotypes found were new: SVIET from Armopa and CVIKT from an isolate in Timika. There was also a strong association (P < 0.0001) between the pfcrt 76T allele and chloroquine resistance in 50 samples. In Papua New Guinea, mutations in the pfcrt gene were observed in 15 isolates with chloroquine minimum inhibitory concentrations (MICs) of 16-64 pmol, while the remaining six isolates, which had a wild-type pfcrt gene at codon 76, had MICs of 2-8 pmol. These observations confirm that mutations at codon 76 in the pfcrt gene are present in both in vivo and in vitro cases of chloroquine resistance, and that detection of the pfcrt 76T allele could predict potential chloroquine treatment failures.

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A disappointing feature of conventional methods for detecting association between DNA variation and a phenotype of interest is that they tell us little about the hidden pattern of linkage disequilibrium (LD) with the functional variant that is actually responsible for the association. This limitation applies to case-control studies and also to the transmission/disequilibrium test (TDT) and other family-based association methods. Here we present a fresh perspective on genetic association based on two novel concepts called 'LD squares' and 'equi-risk alleles'. These describe and characterize the different patterns of gametic LD which underlie genetic association. These concepts lead to a general principle - the Equi-Risk Allele Segregation Principle - which captures the way in which underlying LD patterns affect the transmission patterns of genetic variants associated with a phenotype. This provides a basis for distinguishing the hidden LD patterns and might help to locate the functional variants responsible for the association.

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Gli organismi vegetali mostrano una notevole capacità di adattamento alle condizioni di stress e lo studio delle componenti molecolari alla base dell'adattamento in colture cerealicole di interesse alimentare, come il frumento, è di particolare interesse per lo studio di varietà che consentano una buona produzione con basso input anche in condizioni ambientali non ottimali. L'esposizione delle colture cerealicole a stress termico durante determinate fasi del ciclo vitale influisce negativamente sulla resa e sulla qualità, a questo fine è necessario chiarire le basi genetiche e molecolari della termotolleranza per identificare geni e alleli vantaggiosi da impiegare in programmi di incrocio volti al miglioramento genetico. Numerosi studi dimostrano il coinvolgimento delle sHSP a localizzazione cloroplastica (in frumento sHSP26) nel meccanismo di acquisizione della termotolleranza e la loro interazione con diverse componenti del fotosistema II (PSII) che determinerebbe un’azione protettiva in condizioni di stress termico e altri tipi di stress. Lo scopo del progetto è quello di caratterizzare in frumento duro nuove varianti alleliche correlate alla tolleranza a stress termico mediate l'utilizzo del TILLING (Target Induced Local Lesion In Genome), un approccio di genetica inversa che prevede la mutagenesi e l'identificazione delle mutazioni indotte in siti di interesse. Durante la tesi sono state isolate e caratterizzate 3 sequenze geniche complete per smallHsp26 denominate TdHsp26-A1; TdHsp26-A2; TdHsp26-B1 e un putativo pseudogene denominato TdHsp26-A3. I geni isolati sono stati usati come target in analisi di TILLING in due popolazioni di frumento duro mutagenizzate con EMS (EtilMetanoSulfonato). Nel nostro studio sono stati impiegati due differenti approcci di TILLING: un approccio di TILLING classico mediante screening con High Resolution Melting (HRM) e un approccio innovativo che sfrutta un database di TILLING recentemente sviluppato. La popolazione di mutanti cv. Kronos è stata analizzata per la presenza di mutazioni in tutti e tre i geni individuati mediante ricerca online nel database di TILLING, il quale sfrutta la tecnica dell’exome capture sulla popolazione di TILLING seguito da sequenziamento ad alta processività. Attraverso questa tecnica sono state individuate, nella popolazione mutagenizzata di frumento duro cv. Kronos, 36 linee recanti mutazioni missenso. Contemporaneamente lo screening con HRM, effettuato su 960 genotipi della libreria di TILLING di frumento duro cv. Cham1 ha consentito di individuare mutazioni in una regione di 211bp di interesse funzionale del gene TdHsp26-B1, tra le quali 3 linee mutanti recanti mutazioni missenso in omozigosi. Alcune mutazioni missenso individuate sui due geni TdHsp26-A1 e TdHsp26-B1 sono state confermate in vivo nelle piante delle rispettive linee mutanti generando marcatori codominanti KASP (Kompetitive Allele Specific PCR) con cui è stato possibile verificare anche il grado di zigosità di tali mutazioni. Al fine di ridurre il numero di mutazioni non desiderate nelle linee risultate più interessanti, è stato eseguito il re-incrocio dei mutanti con i relativi parentali wild type ed inoltre sono stati generati alcuni doppi mutanti che consentiranno di comprendere meglio i meccanismi molecolari presieduti da questa classe genica. Gli individui F1 degli incroci sono stati poi genotipizzati con i medesimi marcatori KASP specifici per la mutazione di interesse per verificare la buona riuscita dell’incrocio. Questo approccio ha permesso di individuare ed implementare risorse genetiche utili ad intraprendere studi funzionali relativi al ruolo di smallHSP plastidiche implicate nella acquisizione di termotolleranza in frumento duro e di generare marcatori potenzialmente utili in futuri programmi di breeding.

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Predictive models of peptide-Major Histocompatibility Complex (MHC) binding affinity are important components of modern computational immunovaccinology. Here, we describe the development and deployment of a reliable peptide-binding prediction method for a previously poorly-characterized human MHC class I allele, HLA-Cw*0102.

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Multiple endocrine neoplasia syndromes have since been classified as types 1 and 2, each with specific phenotypic patterns. MEN1 is usually associated with pituitary, parathyroid and paraneoplastic neuroendocrine tumours. The hallmark of MEN2 is a very high lifetime risk of developing medullary thyroid carcinoma (MTC) more than 95% in untreated patients. Three clinical subtypesdMEN2A, MEN2B, and familial MTC (FMTC) have been defined based on the risk of pheochromocytoma, hyperparathyroidism, and the presence or absence of characteristic physical features). MEN2 occurs as a result of germline activating missense mutations of the RET (REarranged during Transfection) proto-oncogene. MEN2-associated mutations are almost always located in exons 10, 11, or 13 through 16. Strong genotype-phenotype correlations exist with respect to clinical subtype, age at onset, and aggressiveness of MTC in MEN2. These are used to determine the age at which prophylactic thyroidectomy should occur and whether screening for pheochromocytoma or hyperparathyroidism is necessary. Specific RET mutations can also impact management in patients presenting with apparently sporadic MTC. Therefore, genetic testing should be performed before surgical intervention in all patients diagnosed with MTC. Recently, Pellegata et al. have reported that germline mutations in CDKN1B can predispose to the development of multiple endocrine tumours in both rats and humans and this new MEN syndrome is named MENX and MEN4, respectively. CDKN1B. A recent report showed that in sporadic MTC, CDKN1B V109G polymorphism correlates with a more favorable disease progression than the wild-type allele and might be considered a new promising prognostic marker. New insights on MEN syndrome pathogenesis and related inherited endocrine disorders are of particular interest for an adequate surgical and therapeutic approach.

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Habitat fragmentation is a major threat to biodiversity, as it can alter ecological processes at various spatial and trophic scales. At the species level, fragmentation leading to the isolation of populations can trigger reductions in genetic diversity, potentially having detrimental effects on population fitness, adaptability and ultimately population persistence. Leptomyrmex pallens is a widespread rainforest ant endemic to New Caledonia but now confined to habitat patches that have been fragmented by anthropogenic fire regimes over the last 200 years. We investigated the social structure of L. pallens in the Aoupinié region (c.a. 4900 ha), and assessed the impacts of habitat fragmentation on its population genetic structure. Allele frequencies at 13 polymorphic microsatellite loci were compared among 411 worker ants from 21 nests distributed across the region. High within-nest relatedness (r = 0.70 ± 0.02), and a single queen found in 38 % of the nests by pedigree analysis indicate that the species is monogynous to weakly polygynous. Estimates of gene flow and genetic structure across the region were subsequently determined using a combined dataset of single workers per nest and of unrelated foraging workers. These estimates coupled with a comprehensive landscape genetic analysis revealed no evidence of significant population structure or habitat effects, suggesting that the Aoupinié region harbours a single panmictic population. In contrast, analyses of mitochondrial DNA sequence data revealed a high degree of genetic structuring, indicating limited maternal gene flow and suggesting that gene flow among nests is driven primarily by winged males. Overall these findings suggest that fire-induced habitat fragmentation has had little impact on the population dynamics of L. pallens. Additional studies of less mobile species should therefore be conducted to gain further insights into fire related disturbances on the unique biodiversity and function of New Caledonian ecosystems.

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The mixed double-decker Eu\[Pc(15C5)4](TPP) (1) was obtained by base-catalysed tetramerisation of 4,5-dicyanobenzo-15-crown-5 using the half-sandwich complex Eu(TPP)(acac) (acac = acetylacetonate), generated in situ, as the template. For comparative studies, the mixed triple-decker complexes Eu2\[Pc(15C5)4](TPP)2 (2) and Eu2\[Pc(15C5)4]2(TPP) (3) were also synthesised by the raise-by-one-story method. These mixed ring sandwich complexes were characterised by various spectroscopic methods. Up to four one-electron oxidations and two one-electron reductions were revealed by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). As shown by electronic absorption and infrared spectroscopy, supramolecular dimers (SM1 and SM3) were formed from the corresponding double-decker 1 and triple-decker 3 in the presence of potassium ions in MeOH/CHCl3.

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At the turn of the century in Melbourne, a notice typed on the verso of a postcard stated that the South Yarra Baptist Young Men's class was meeting on the following Sunday at 2.45 p.m. The card, published in the United Kingdom, was numbered 51828 in the Valentine series of Papuan postcards.1 The image, a photograph of Hanuabada village taken in the early 1880s, and the text, written early in 1900, are contradictory and constitute separate realms of evidence that invite a renegotiation of meaning, analysis, and interpretation of the relationships between images, tourism, colonial rule, and ethnographic knowing. The visual evidence suggests the postcard may have played an ethnographic, educative role in the public understanding of Papua, which had just become an Australian Territory and was not yet well known. It is also suggestive of educative roles related to mission endeavours, subimperialist ambitions and the new tourist traffic through the ports of Port Moresby, Samarai, and Rabaul.

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A low temperature synthesis method based on the decomposition of urea at 90°C in water has been developed to synthesise fraipontite. This material is characterised by a basal reflection 001 at 7.44 Å. The trioctahedral nature of the fraipontite is shown by the presence of a 06l band around 1.54 Å, while a minor band around 1.51 Å indicates some cation ordering between Zn and Al resulting in Al-rich areas with a more dioctahedral nature. TEM and IR indicate that no separate kaolinite phase is present. An increase in the Al content however, did result in the formation of some SiO2 in the form of quartz. Minor impurities of carbonate salts were observed during the synthesis caused by to the formation of CO32- during the decomposition of urea.

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