Home About us Contact
|
Home About us Contact | ||
|
|
||
Molecular Genetic Techniques (molecular + genetic_techniques)
Selected AbstractsMolecular genetic analysis of haematological malignancies: I. Acute leukaemias and myeloproliferative disordersINTERNATIONAL JOURNAL OF LABORATORY HEMATOLOGY, Issue 3 2005A. J. BENCH Summary Molecular genetic techniques are now routinely applied to haematological malignancies within a clinical laboratory setting. The detection of genetic rearrangements not only assists with diagnosis and treatment decisions, but also adds important prognostic information. In addition, genetic rearrangements associated with leukaemia can be used as molecular markers allowing the detection of low levels of residual disease. This review will concentrate on the application of molecular genetic techniques to the acute leukaemias and myeloprolferative disorders. [source] Development of a daphnia magna DNA microarray for evaluating the toxicity of environmental chemicalsENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 4 2007Hajime Watanabe Abstract Toxic chemical contaminants have a variety of detrimental effects on various species, and the impact of pollutants on ecosystems has become an urgent issue. However, the majority of studies regarding the effects of chemical contaminants have focused on vertebrates. Among aquatic organisms, Daphnia magna has been used extensively to evaluate organism- and populationlevel responses of invertebrates to pollutants in acute toxicity or reproductive toxicity tests. Although these types of tests can provide information concerning hazardous concentrations of chemicals, they provide no information about their mode of action. Recent advances in molecular genetic techniques have provided tools to better understand the responses of aquatic organisms to pollutants. In the present study, we adapted some of the techniques of molecular genetics to develop new tools, which form the basis for an ecotoxicogenomic assessment of D. magna. Based on a Daphnia expressed sequence tag database, we developed an oligonucleotide-based DNA microarray with high reproducibility. The DNA microarray was used to evaluate gene expression profiles of neonatal daphnids exposed to several different chemicals: Copper sulfate, hydrogen peroxide, pentachlorophenol, or ,-naphthoflavone. Exposure to these chemicals resulted in characteristic patterns of gene expression that were chemical-specific, indicating that the Daphnia DNA microarray can be used for classification of toxic chemicals and for development of a mechanistic understanding of chemical toxicity on a common freshwater organism. [source] The role of genetic testing in soft tissue sarcomaHISTOPATHOLOGY, Issue 1 2006C R Antonescu Soft tissue tumours represent a heterogeneous group of mesenchymal lesions and their classification continues to evolve as a result of incorporating advances in cytogenetic and molecular techniques. In the last decade traditional diagnostic approaches were supplemented with a significant number of reliable molecular diagnostic tools, detecting tumour type-specific genetic alterations. In addition, the successful application of some of these techniques to formalin-fixed paraffin-embedded tissue made it possible to subject a broader range of clinical material to molecular analysis. Thus, molecular genetics has already become an integral part of the work-up in some tumours, such as paediatric small blue round cell tumours, which demonstrate characteristic translocations. Several lines of evidence suggest that sarcomas can be divided into two major genetic groups: (i) sarcomas with specific genetic alterations and usually simple karyotypes, such as reciprocal chromosomal translocations (e.g. FUS-DDIT3 in myxoid liposarcoma) and specific oncogenic mutations (e.g. KIT mutation in gastrointestinal stromal tumours); and (i) sarcomas with non-specific genetic alterations and complex unbalanced karyotypes. Some of these genetic abnormalities, including chromosomal numerical changes, translocations, gene amplifications or large deletions can be apparent at the cytogenetic level (karyotyping, fluoresence in situ hybridization), while others, such as small deletions, insertions or point mutations, require molecular genetic techniques (polymerase chain reaction and sequence analysis). This review focuses on the applicability of genetic testing in the diagnosis and prognosis of soft tissue sarcomas, and gives a realistic appraisal of the ancillary role of molecular techniques, including its advantages and limitations. [source] Molecular genetic analysis of haematological malignancies: I. Acute leukaemias and myeloproliferative disordersINTERNATIONAL JOURNAL OF LABORATORY HEMATOLOGY, Issue 3 2005A. J. BENCH Summary Molecular genetic techniques are now routinely applied to haematological malignancies within a clinical laboratory setting. The detection of genetic rearrangements not only assists with diagnosis and treatment decisions, but also adds important prognostic information. In addition, genetic rearrangements associated with leukaemia can be used as molecular markers allowing the detection of low levels of residual disease. This review will concentrate on the application of molecular genetic techniques to the acute leukaemias and myeloprolferative disorders. [source] Extra pair paternity in birds: a review of interspecific variation and adaptive functionMOLECULAR ECOLOGY, Issue 11 2002Simon C. Griffith Abstract The application of molecular genetic techniques has revolutionized our view of avian mating systems. Contrary to prior expectations, birds are only very rarely sexually monogamous, with ,extra-pair offspring' found in approximately 90% of species. Even among socially monogamous species, over 11% of offspring are, on average, the result of extra-pair paternity (EPP). Based on over 150 molecular genetic studies of EPP in birds, we review two topical areas: (i) ecological explanations for interspecific variation in the rate of EPP; and (ii) evidence bearing on the adaptive function of EPP. We highlight the remaining challenges of understanding the relative roles of genes and ecology in determining variation between taxa in the rate of extra paternity, and testing for differences between extra-pair offspring and those sired within-pair. [source] Plasmid DNA transfer in Mycobacterium smegmatis involves novel DNA rearrangements in the recipient, which can be exploited for molecular genetic studiesMOLECULAR MICROBIOLOGY, Issue 4 2004Jun Wang Summary The establishment of molecular genetic techniques is essential for development of new treatments for mycobacterial infections. To this end, we recently described a novel DNA transfer process that occurs in the model mycobacterial organism Mycobacterium smegmatis. This transfer system is most like conjugal DNA transfer in that it requires two viable parents, is DNAse resistant and occurs between distinct donor and recipient strains. Cis -acting sequences called bom, which confer transferability, are distinct from the prototypical oriT sites of conjugative plasmids, as they occur at multiple locations in the chromosome and require RecA in the recipient to mediate plasmid recircularization. Here, we show that a plasmid containing two of these bom regions can undergo several fates in the recipient cell, each of which require recipient recombination functions. The products of plasmid transfer that we observed provide further insights toward a model for DNA transfer. Furthermore, we have taken advantage of the recombination events that occur in the recipient to develop simple procedures for capturing, or replacing specific segments of the recipient chromosome. To demonstrate the potential of the system, we describe the capture and deletion of 25 kb of the M. smegmatis chromosome, and targeted-allele exchange of the recipient recB and recD genes. Using these transfer-mediated rearrangements, we demonstrate that homology with the recipient chromosome and RecB, but not RecD, are essential for DNA transfer. [source] Mutation screening in the ryanodine receptor 1 gene (RYR1) in patients susceptible to malignant hyperthermia who show definite IVCT results: identification of three novel mutationsACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 6 2002H. Rueffert Background: The ryanodine receptor of the skeletal muscle (RYR1) seems to be of outstanding importance in the pathogenesis of malignant hyperthermia (MH). It has been shown that point mutations in the RYR1 gene are strongly associated with the MH phenotype. A correctly determined phenotype is the basic prerequisite for adequate genetic MH screening. In this study we examined only those MH susceptible patients for the presence of potential RYR1 mutations who showed strong pathological muscle responses in the in vitro contracture test (IVCT). Methods: A total of 56 MHS index patients who complied with the following IVCT criteria were included in the molecular genetic investigation: Contracture forces ,4 mN at a caffeine concentration of 2.0 mmol/l and ,8 mN at a halothane concentration of 0.44 mmol/l. DNA sequences of exons 2, 6, 9, 11, 12, 14, 15, 17, 39, 40, 45, 46, 102 of the RYR1 gene were analysed by the direct sequencing technique. Furthermore, if an MH mutation was identified in an index patient, all relatives were screened for their family specific RYR1 defect. Results: In 39 index patients an RYR1 mutation was detected: Arg163Cys (n = 2), Asp166Asn (n = 1), Gly341Arg (n = 2), Arg401His (n = 2), Arg614Cys (n = 12), Asp2129Glu (n = 1),Vol2168Met (n = 1), Thr2206Met (n = 9), Ala2428Thr (n = 1), Gly2434Arg (n = 2), Arg2435His (n = 1), Arg2452Trp (n = 1), Arg2454His (n = 4). Three new RYR1 mutations were identified. We found a potential MH mutation in a further 130 relatives of the 39 index patients. Thirty-seven individuals were classified as MHS exclusively by molecular genetic techniques and did not have to undergo the IVCT. Conclusions: The ascertained high rate of successful MH mutation screening (69.64%) is obviously associated with the more clearly defined MHS diagnosis in the IVCT. According to the EMHG guidelines for the molecular genetic detection of MH susceptibility, a positive MH disposition could be determined in numerous persons by a less invasive technique. [source] External quality assessment of rapid prenatal detection of numerical chromosomal aberrations using molecular genetic techniques: 3 years experiencePRENATAL DIAGNOSIS, Issue 5 2007S. C. Ramsden Abstract Objectives Prenatal diagnosis using rapid molecular genetic techniques is now a widely used method for detecting the most prevalent chromosomal aneuploidies. The object of this work was to develop a methodology for delivering external quality assessment (EQA) appropriate to the needs of routine diagnostic testing laboratories. Methods We have provided three rounds of EQA using 15 different samples over 3 years. The scheme has developed to assess both the genotyping accuracy of the results and the appropriateness of the clinical reports issued to the referring clinician. Results Participation in the EQA scheme has increased from 9 to 27 laboratories from across Europe over the three sample distributions. All laboratories have used quantitative fluorescence-PCR (QF-PCR) to analyse these samples except for a sole participant in 2006 who used multiplex ligation-dependent probe amplification (MLPA). In total 265 samples have been distributed, of which four (1.5%) were not reported due to technical failures and one (0.4%) was reported incorrectly and must be regarded as a genotyping error. Conclusions We have demonstrated a significant and increasing demand for EQA in the rapid detection of aneuploidies in UK and other European laboratories. Using the methodologies described, we have had a very low rate of technical failures and demonstrated a high level of genotyping accuracy. However, the quality of the clinical reports was variable and suggestions are made for improvement. Copyright © 2007 John Wiley & Sons, Ltd. [source] Male-mediated introgression of Bos indicus genes into Argentine and Bolivian Creole cattle breedsANIMAL GENETICS, Issue 5 2000G Giovambattista The geographic distribution and frequency of Bos taurus and Bos indicus Y chromosome haplotypes amongst Argentine and Bolivian Creole cattle breeds were studied, using cytogenetic and molecular genetic techniques. A complete correspondence between Y chromosome morphology and the haplotype of the Y-linked microsatellite marker INRA 124 was found in all males examined. The taurine and indicine haplotypes were detected in 85·7 and 14·3% of the males studied, respectively, although these frequencies varied amongst the different breeds examined. The geographic distribution of this polymorphism suggests a pattern of zebu introgression in South America. The highest frequencies of the Zebu Y-chromosome are found in Brazilian populations (43,90%), in the eastern part of the continent, while it is absent in the southermost breeds from Uruguay and Argentina. Bolivan breeds, at the centre of the continent, exhibit intermediate values (17,41%). This east/west and north/south gradient of male Zebu introgression could be explained by historical events and environmental factors. [source] | |||||||||||||