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DNA Profiles (dna + profile)
Selected AbstractsMixture Interpretation: Defining the Relevant Features for Guidelines for the Assessment of Mixed DNA Profiles in Forensic Casework,JOURNAL OF FORENSIC SCIENCES, Issue 4 2009Bruce Budowle Ph.D. Abstract:, Currently in the United States there is little direction for what constitutes sufficient guidelines for DNA mixture interpretation. While a standardized approach is not possible or desirable, more definition is necessary to ensure reliable interpretation of results is carried out. In addition, qualified DNA examiners should be able to review reports and understand the assumptions made by the analyst who performed the interpretation. Interpretation of DNA mixture profiles requires consideration of a number of aspects of a mixed profile, many of which need to be established by on-site, internal validation studies conducted by a laboratory's technical staff, prior to performing casework analysis. The relevant features include: criteria for identification of mixed specimens, establishing detection and interpretation threshold values, defining allele peaks, defining nonallele peaks, identifying artifacts, consideration of tri-allelic patterns, estimating the minimum number of contributors, resolving components of a mixture, determining when a portion of the mixed profile can be treated as a single source profile, consideration of potential additive effects of allele sharing, impact of stutter peaks on interpretation in the presence of a minor contributor, comparison with reference specimens, and some issues related to the application of mixture calculation statistics. Equally important is using sensible judgment based on sound and documented principles of DNA analyses. Assumptions should be documented so that reliable descriptive information is conveyed adequately concerning that mixture and what were the bases for the interpretations that were carried out. Examples are provided to guide the community. Interpretation guidelines also should incorporate strategies to minimize potential bias that could occur by making inferences based on a reference sample. The intent of this paper is to promote more thought, provide assistance on many aspects for consideration, and to support that more formalized mixture interpretation guidelines are developed. [source] Least-Square Deconvolution: A Framework for Interpreting Short Tandem Repeat Mixtures,JOURNAL OF FORENSIC SCIENCES, Issue 6 2006Tsewei Wang Ph.D. ABSTRACT: Interpreting mixture short tandem repeat DNA data is often a laborious process, involving trying different genotype combinations mixed at assumed DNA mass proportions, and assessing whether the resultant is supported well by the relative peak-height information of the mixture sample. If a clear pattern of major,minor alleles is apparent, it is feasible to identify the major alleles of each locus and form a composite genotype profile for the major contributor. When alleles are shared between the two contributors, and/or heterozygous peak imbalance is present, it becomes complex and difficult to deduce the profile of the minor contributor. The manual trial and error procedures performed by an analyst in the attempt to resolve mixture samples have been formalized in the least-square deconvolution (LSD) framework reported here for two-person mixtures, with the allele peak height (or area) information as its only input. LSD operates on the peak-data information of each locus separately, independent of all other loci, and finds the best-fit DNA mass proportions and calculates error residual for each possible genotype combination. The LSD mathematical result for all loci is then to be reviewed by a DNA analyst, who will apply a set of heuristic interpretation guidelines in an attempt to form a composite DNA profile for each of the two contributors. Both simulated and forensic peak-height data were used to support this approach. A set of heuristic guidelines is to be used in forming a composite profile for each of the mixture contributors in analyzing the mathematical results of LSD. The heuristic rules involve the checking of consistency of the best-fit mass proportion ratios for the top-ranked genotype combination case among all four- and three-allele loci, and involve assessing the degree of fit of the top-ranked case relative to the fit of the second-ranked case. A different set of guidelines is used in reviewing and analyzing the LSD mathematical results for two-allele loci. Resolution of two-allele loci is performed with less confidence than for four- and three-allele loci. This paper gives a detailed description of the theory of the LSD methodology, discusses its limitations, and the heuristic guidelines in analyzing the LSD mathematical results. A 13-loci sample case study is included. The use of the interpretation guidelines in forming composite profiles for each of the two contributors is illustrated. Application of LSD in this case produced correct resolutions at all loci. Information on obtaining access to the LSD software is also given in the paper. [source] Occupational tuberculosis following extremely short exposureTHE CLINICAL RESPIRATORY JOURNAL, Issue 1 2009Zaza Kamper-Jørgensen Abstract Introduction:, Transmission of Mycobacterium tuberculosis (MT) in most cases requires extended exposure. Objectives:, To document that MT transmission may occur even after very short exposure. Material and Methods:, All first-time culture-confirmed tuberculosis (TB) cases in Denmark have since 1992 been subjected to genotyping, using the IS6110 -Restriction Fragment Length Polymorphism (RFLP) technique. A young nurse with no risk factors developed pulmonary TB: the DNA pattern of her MT strain was compared to The Danish TB Subtyping Database, comprising >6000 DNA patterns from TB patients nationwide. Results:, Only one single MT DNA pattern matched the DNA profile of the isolate from the nurse. The pattern originated from a patient shortly admitted to the department where she worked at the time. MT transmission had occurred in spite of very short exposure. Conclusion:, By adding modern molecular epidemiological methods to traditional epidemiological surveys, a more detailed picture of MT-transmission pathways can be obtained, showing that MT transmission can occur even after extremely short exposure. This stresses the necessity for adequate respiratory protection among hospital staff taking care of patients with pulmonary symptoms suspected for TB. Please cite this paper as: Kamper-Jørgensen Z, Lillebaek T and Andersen ÅB. Occupational tuberculosis following extremely short exposure. The Clinical Respiratory Journal 2009; 3: 55,57. [source] Prognostic significance of tumour angiogenesis in schistosoma-associated adenocarcinoma of the urinary bladderBJU INTERNATIONAL, Issue 1 2002E. El Sobky Objective To report on tumour angiogenesis and its relationship with morphological variables and prognosis in adenocarcinoma of the urinary bladder associated with schistosomiasis. Patients and methods Fifty-five vesical adenocarcinomas were evaluated from 30 men and 25 women (mean age 47.2 years, sd 8.7, range 30,65) who were followed up after radical cystectomy and urinary diversion for a mean (sd, range) of 61 (43.5, 2.7,159.5) months. Vessels were stained immunohistochemically using an antibody to the platelet endothelial cell-adhesion molecule CD31. Microvessels were counted in active areas of angiogenesis within the tumours (at ×,250) and the microvessel density (MVD) quantified using the mean of three counts. Treatment failure was defined as death from cancer or the development of local recurrence or distant metastasis. Kaplan-Meier survival curves and Cox's proportional hazard model were used to assess survival. Results The overall 5- and 10-year survival rates were 57% and 51%, respectively. The presence of lymph node metastasis and high mean vascular density (> 26) were significantly associated with a poor prognosis. The 5-year survival for patients with negative lymph nodes was 66% while no patients with positive nodes survived for 5 years (P < 0.001); the survival was 72% for patients with a low MVD and 33% for those with a high MVD (P = 0.0016). From individual results plotted against vascularity in lymph node-negative patients, there was a significantly better outcome for those with a low MVD ( 26; P = 0.0099); this significance was maintained on multivariate analysis. However, there was no significant relationship between angiogenesis and the different clinicopathological factors apart from the grade (P = 0.03); tumour stage, grade and DNA profile had no significant effect on survival in these patients. Conclusions These findings suggest that assessing angiogenesis using the MVD provides an independent predictor of survival in patients with adenocarcinoma of the urinary bladder. [source] Applications of the rep-PCR DNA fingerprinting technique to study microbial diversity, ecology and evolutionENVIRONMENTAL MICROBIOLOGY, Issue 4 2009Satoshi Ishii Summary A large number of repetitive DNA sequences are found in multiple sites in the genomes of numerous bacteria, archaea and eukarya. While the functions of many of these repetitive sequence elements are unknown, they have proven to be useful as the basis of several powerful tools for use in molecular diagnostics, medical microbiology, epidemiological analyses and environmental microbiology. The repetitive sequence-based PCR or rep-PCR DNA fingerprint technique uses primers targeting several of these repetitive elements and PCR to generate unique DNA profiles or ,fingerprints' of individual microbial strains. Although this technique has been extensively used to examine diversity among variety of prokaryotic microorganisms, rep-PCR DNA fingerprinting can also be applied to microbial ecology and microbial evolution studies since it has the power to distinguish microbes at the strain or isolate level. Recent advancement in rep-PCR methodology has resulted in increased accuracy, reproducibility and throughput. In this minireview, we summarize recent improvements in rep-PCR DNA fingerprinting methodology, and discuss its applications to address fundamentally important questions in microbial ecology and evolution. [source] Interpreting DNA Evidence: A ReviewINTERNATIONAL STATISTICAL REVIEW, Issue 3 2003L.A. Foreman Summary The paper provides a review of current issues relating to the use of DNA profiling in forensic science. A short historical section gives the main statistical milestones that occurred during a rapid development of DNA technology and operational uses. Greater detail is then provided for interpretation issues involving STR DNA profiles, including: , methods that take account of population substructure in DNA calculations; , parallel work carried out by the US National Research Council; , the move away from multiple independence testing in favour of experiments that demonstrate the robustness of casework procedures; , the questionable practice of source attribution ,with reasonable scientific certainty'; , the effect on the interpretation of profiles obtained under increasingly sensitive techniques, the LCN technique in particular; , the use of DNA profiles as an intelligence tool; , the interpretation of DNA mixtures. Experience of presenting DNA evidence within UK courts is also discussed. The paper then summarises a generic interpretation framework based on the concept of likelihood ratio within a hierarchy of propositions. Finally the use of Bayesian networks to interpret DNA evidence is reviewed. Résumé Cet article présente un inventaire des questions relativesá l'utilisation du profilage ADN dans la science légale. Une courte section historique décrit les principales étapes statistiques qui ont eu lieu pendant le rapide développement de la technologie ADN et ses utilisations opérationnelles. De plus grands détails sont ensuite donnés pour l'interprétation de questions sur les profils AND STR, ce qui inclut: ,les méthodes qui tiennent compte des sous-structures de population dans les calculs ADN; ,le travail conduit en paralléle par le Conseil de Recherche Nationale des Etats-Unis (NRC); ,l'évolution depuis les tests d'indépendance multiple vers des expériences qui démontrent la robustesse des procédures; ,la pratique contestable de l'attribution de source avec "certitude scientifique raisonnable"; ,l'effet de l'interprétation des profils obtenus sous techniques de plus en plus sensibles, la technique LCN en particulier ,l'utilisation de profils ADN comme outil d'intelligence; ,l'interprétation de mélanges ADN. L'expérience de ce type de preuve dans les tribunaux britanniques sera également présentée et commentée. L'article présentera un cavenas d'interprétation centré sur le concept de rapport de vraisemblance, inscrit dans une hérarchie de propositions. Finalement, l'utilisation de réseaux Bayesien pour interpréter la preuve par ADN sera abordée. [source] Evolution of a degradative bacterial consortium during the enrichment of naphtha solventJOURNAL OF APPLIED MICROBIOLOGY, Issue 6 2000L. Cavalca A microbial mixed culture able to degrade naphtha solvent, a model of hydrocarbon aromatic mixture, was isolated from a hydrocarbon-polluted soil. Composition of the population was monitored by phenotypic and molecular methods applied on soil DNA, on whole enrichment culture DNA, and on 85 isolated strains. Strains were characterized for their 16S rDNA restriction profiles and for their random amplified polymorphic DNA profiles. Catabolic capabilities were monitored by phenotypic traits and by PCR assays for the presence of the catabolic genes methyl mono-oxygenase ( xylA,M), catechol 2,3 dioxygenase (xylE) and toluene dioxygenase (todC1) of TOL and TOD pathways. Different haplotypes belonging to Pseudomonas putida, Ps. aureofaciens and Ps. aeruginosa were found to degrade aromatic compounds and naphtha solvent. The intrinsic catabolic activity of the microbial population of the polluted site was detected by PCR amplification of the xylE gene directly from soil DNA. [source] Environmental- and parental condition-related variation in sex ratio of kestrel broodsJOURNAL OF AVIAN BIOLOGY, Issue 2 2000Erkki Korpimäki Variation of brood sex ratio was studied in a Finnish population of Eurasian Kestrels Falco tinnunculus breeding in an unpredictably variable environment. From those young that survived until 2,4 weeks of age, blood was collected and their sex determined from polymorphic DNA profiles produced by hybridisation with a human minisatellite probe. The sex ratio was male-biased during a year of food (vole) scarcity. Furthermore, in broods without mortality, contrasting seasonal trends in sex ratios emerged. In this subsample, the proportion of males increased with later laying date during years of low and moderate food supply, whereas the opposite was true in a year of relatively high food supply. These trends may indicate circumstances that favour the raising of different sex. The proportion of males in the brood was negatively correlated with body condition of both male and female parents, also reflecting an adaptive condition-dependent sex-ratio adjustment, or alternatively the inability of the parents to meet the requirements of the more energetically expensive female offspring. We discuss the limitations that unpredictable conditions during brood raising can impose on adaptive sex-ratio manipulation, particularly in species with sexual size dimorphism and consequent differences in the cost of raising the two sexes. [source] Comparison of Presumptive Blood Test Kits Including Hexagon OBTIJOURNAL OF FORENSIC SCIENCES, Issue 3 2008Emma Johnston M.Sc. Abstract:, Four presumptive blood tests, Hexagon OBTI, Hemastix®, Leucomalachite green (LMG), and Kastle-Meyer (KM) were compared for their sensitivity in the identification of dried bloodstains. Stains of varying blood dilutions were subjected to each presumptive test and the results compared. The Hexagon OBTI buffer volume was also reduced to ascertain whether this increased the sensitivity of the kit. The study found that Hemastix® was the most sensitive test for trace blood detection. Only with the reduced buffer volume was the Hexagon OBTI kit as sensitive as the LMG and KM tests. However, the Hexagon OBTI kit has the advantage of being a primate specific blood detection kit. This study also investigated whether the OBTI buffer within the kit could be utilized for DNA profiling after presumptive testing. The results show that DNA profiles can be obtained from the Hexagon OBTI kit buffer directly. [source] Identification of Biological Samples in a Case of Contamination of a Cytological Slide Preparation,JOURNAL OF FORENSIC SCIENCES, Issue 3 2008Anke Junge Ph.D. Abstract:, Here we report a case where a discrete section of the cytological slide preparation of a female individual was obviously contaminated with pleura liquid of a female tumor patient. Analysis of the cancerous pleura liquid and the healthy cells of the slide preparation showed different DNA profiles, indicating that the material originated from two different female individuals. The DNA profile of the cell mixture revealed a heterogenous pattern whereby the alleles could be assigned to the healthy and the tumor patient. Loss of heterozygosity (LOH) was observed in four of eight short tandem repeat systems for the pleura liquid and the cell mixture. Despite the low amount of DNA on the slide preparation and the occurrence of LOH, it was possible to clarify the case and to support the assumption that a drop of cancerous pleura liquid contaminated the cytological slide. [source] Y-STR Profiling in Extended Interval (,3 days) Postcoital Cervicovaginal Samples,JOURNAL OF FORENSIC SCIENCES, Issue 2 2008Kathleen A. Mayntz-Press M.S. Abstract:, Depending upon specific situations, some victims of sexual assault provide vaginal samples more than 36,48 h after the incident. We have tested the ability of commercial and in-house Y-STR systems to provide DNA profiles from extended interval (,3 days) postcoital samples. The commercial Y-STR systems tested included the AmpF,STR® YfilerÔ (Applied Biosystems), PowerPlex® Y (Promega) and Y-PLEXÔ 12 (Reliagene) products whereas the in-house systems comprised Multiplex I (MPI) and Multiplex B (MPB). Three donor couples were recruited for the study. Postcoital cervicovaginal swabs (x2) were recovered by each of the three females at specified intervals after sexual intercourse (3,7 days). Each time point sample was collected after a separate act of sexual intercourse and was preceded by a 7-day abstention period. As a negative control, a precoital swab was also recovered prior to coitus for each sampling and only data from postcoital samples that demonstrated a lack of male DNA in the associated precoital sample was used. A number of DNA profile enhancement strategies were employed including sampling by cervical brushing, nondifferential DNA extraction methodology, and post-PCR purification. Full Y-STR profiles from cervicovaginal samples recovered 3,4 days after intercourse were routinely obtained. Profiles were also obtainable 5,6 days postcoitus although by this stage partial profiles rather than full profiles were a more likely outcome. The DNA profiles from the sperm fraction of a differential lysis were superior to that obtained when a nondifferential method was employed in that the allelic signal intensities were generally higher and more balanced and exhibited less baseline noise. The incorporation of a simple post-PCR purification process significantly increased the ability to obtain Y-STR profiles, particularly from 5- to 6-day postcoital samples. Remarkably an 8 locus Y-STR profile was obtained from a 7-day postcoital sample, which is approaching the reported time limit for sperm detection in the cervix. [source] Inferences from DNA data: population histories, evolutionary processes and forensic match probabilitiesJOURNAL OF THE ROYAL STATISTICAL SOCIETY: SERIES A (STATISTICS IN SOCIETY), Issue 2 2003Ian J. Wilson Summary. We develop a flexible class of Metropolis,Hastings algorithms for drawing inferences about population histories and mutation rates from deoxyribonucleic acid (DNA) sequence data. Match probabilities for use in forensic identification are also obtained, which is particularly useful for mitochondrial DNA profiles. Our data augmentation approach, in which the ancestral DNA data are inferred at each node of the genealogical tree, simplifies likelihood calculations and permits a wide class of mutation models to be employed, so that many different types of DNA sequence data can be analysed within our framework. Moreover, simpler likelihood calculations imply greater freedom for generating tree proposals, so that algorithms with good mixing properties can be implemented. We incorporate the effects of demography by means of simple mechanisms for changes in population size and structure, and we estimate the corresponding demographic parameters, but we do not here allow for the effects of either recombination or selection. We illustrate our methods by application to four human DNA data sets, consisting of DNA sequences, short tandem repeat loci, single-nucleotide polymorphism sites and insertion sites. Two of the data sets are drawn from the male-specific Y-chromosome, one from maternally inherited mitochondrial DNA and one from the , -globin locus on chromosome 11. [source] Discrimination of Arcobacter butzleri isolates by polymerase chain reaction-mediated DNA fingerprintingLETTERS IN APPLIED MICROBIOLOGY, Issue 2 2002H.I. Atabay Aims:,The objective of this study was to subtype Arcobacter butzleri isolates using RAPD-PCR. Methods and Results:,Thirty-five A. butzleri isolates obtained from chicken carcasses were examined. PCR-mediated DNA fingerprinting technique with primers of the variable sequence motifs was used to detect polymorphism within the isolates. Eleven distinct DNA profiles were obtained as follows: Of the 35 strains, 10 as profile 4; seven as profile 1; five as profile 3; three as profiles 2 and 9; two as profile 10; one as profiles 5, 6, 7, 8 and 11. Conclusions:,Chicken carcasses sold in markets were found to be contaminated with several different strains of A. butzleri. RAPD-PCR technique was found to be a useful technique for distinguishing A. butzleri isolates. Significance and Impact of the Study:,The presence of several different A. butzleri strains on chicken carcasses may indicate multiple sources of contamination. The epidemiological role of A. butzleri in human and animal diseases should be investigated further. [source] Genetic continuity after the collapse of the Wari empire: Mitochondrial DNA profiles from Wari and post-Wari populations in the ancient AndesAMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 1 2009Brian M. Kemp Abstract The Wari empire flourished in the central, highland Peruvian Andes from AD 600,1000, and although the events that led to its demise are unknown, archaeological evidence indicates that Wari control waned at the end of the first millennium. Here, we test the hypothesis that, despite the major shift in social and political organization at the fall of the Wari empire, the mitochondrial DNA (mtDNA) composition of populations from the Ayacucho Basin, the former imperial heartland of the empire, remained essentially unchanged. Results show that mtDNA haplogroup frequencies among the Wari and post-Wari groups differ, but the difference is not statistically significant (,2 = 5.886, df = 3, P = 0.1172). This is the first study in the Andes to use haplotypic data to evaluate the observed genetic distance between two temporally distinct prehispanic populations (FST = 0.029) against modeled expectations of four possible evolutionary scenarios. None of these simulations allowed the rejection of continuity. In total, at both the haplogroup and haplotype levels these data do not allow us to reject the hypothesis that post-Wari individuals sampled in this study are the maternal descendants of those sampled from the Wari era site of Conchopata. However, genetic homogeneity in the mitochondrial gene pool, as seen in the late prehispanic southern Andes, may also characterize our study region. But, prior to this research, this was unknown. If our new data show mtDNA homogeneity, then this could limit the detection of female migration if, in fact, it occurred. Nonetheless, the novel mtDNA data presented here currently do not support the hypothesis that there was an influx of genetically distinct females into the former Wari heartland after the Wari collapse. Am J Phys Anthropol, 2009. © 2009 Wiley-Liss, Inc. [source] Ethics and Genetic Selection in Purebred DogsREPRODUCTION IN DOMESTIC ANIMALS, Issue 1 2003VN Meyers-Wallen Contents There is an ongoing revolution in medicine that is changing the way that veterinarians will be counselling clients regarding inherited disorders. Clinical applications will emerge rapidly in veterinary medicine as we obtain new information from canine and comparative genome projects (Meyers-Wallen 2001: Relevance of the canine genome project to veterinary medical practice. International Veterinary Information Service, New York). The canine genome project is described by three events: mapping markers on canine chromosomes, mapping gene locations on canine chromosomes (Breen et al. 2001: Genome Res. 11, 1784,1795), and obtaining the nucleotide sequence of the entire canine genome. Information from such research has provided a few DNA tests for single gene mutations [Aguirre 2000: DNA testing for inherited canine diseases. In: Bonagura, J (ed), Current Veterinary Therapy XIII. Philadelphia WB Saunders Co, 909,913]. Eventually it will lead to testing of thousands of genes at a time and production of DNA profiles on individual animals. The DNA profile of each dog could be screened for all known genetic disease and will be useful in counselling breeders. As part of the pre-breeding examination, DNA profiles of prospective parents could be compared, and the probability of offspring being affected with genetic disorders or inheriting desirable traits could be calculated. Once we can examine thousands of genes of individuals easily, we have powerful tools to reduce the frequency of, or eliminate, deleterious genes from a population. When we understand polygenic inheritance, we can potentially eliminate whole groups of deleterious genes from populations. The effect of such selection on a widespread basis within a breed could rapidly improve health within a few generations. However, until we have enough information on gene interaction, we will not know whether some of these genes have other functions that we wish to retain. And, other population effects should not be ignored. At least initially it may be best to use this new genetic information to avoid mating combinations that we know will produce affected animals, rather than to eliminate whole groups of genes from a population. This is particularly important for breeds with small gene pools, where it is difficult to maintain genetic diversity. Finally, we will eventually have enough information about canine gene function to select for specific genes encoding desirable traits and increase their frequencies in a population. This is similar to breeding practices that have been applied to animals for hundreds of years. The difference is that we will have a large pool of objective data that we can use rapidly on many individuals at a time. This has great potential to improve the health of the dog population as a whole. However, if we or our breeder clients make an error, we can inadvertently cause harm through massive, rapid selection. Therefore, we should probably not be advising clients on polygenic traits or recommend large scale changes in gene frequencies in populations until much more knowledge of gene interaction is obtained. By then it is likely that computer modelling will be available to predict the effect of changing one or several gene frequencies in a dog population over time. And as new mutations are likely to arise in the future, these tools will be needed indefinitely to detect, treat and eliminate genetic disorders from dog populations. Information available from genetic research will only be useful in improving canine health if veterinarians have the knowledge and skills to use it ethically and responsibly. There is not only a great potential to improve overall canine health through genetic selection, but also the potential to do harm if we fail to maintain genetic diversity. Our profession must be in a position to correctly advise clients on the application of this information to individual dogs as well as to populations of dogs, and particularly purebred dogs. [source] The first major extended-spectrum ,-lactamase outbreak in Scandinavia was caused by clonal spread of a multiresistant Klebsiella pneumoniae producing CTX-M-15,APMIS, Issue 4 2008BIRGITTA LYTSY Between May and December 2005, 64 multidrug-resistant isolates of Klebsiella pneumoniae were detected from patients admitted to Uppsala University Hospital. This represented a dramatic increase in ESBL-producing K. pneumoniae compared to previous years. To investigate the epidemiology and to characterize the resistance mechanisms of the isolates, a study was initiated. Antibiotic susceptibility was determined by means of the Etest and the disc diffusion method. Extended-spectrum beta-lactamase (ESBL) production was identified by clavulanic acid synergy test and confirmed with PCR amplification followed by DNA sequencing. DNA profiles of the isolates were examined with pulsed-field gel electrophoresis (PFGE). All isolates were resistant or exhibited reduced susceptibility to cefadroxil, cefuroxime, cefotaxime, ceftazidime, aztreonam, piperacillin/tazobactam, ciprofloxacin, tobramycin, and trimethoprim-sulfamethoxazole. They produced ESBL of the CTX-M-15 type, and the involvement of a single K. pneumoniae clone was shown. This is the first major clonal outbreak of multiresistant ESBL-producing K. pneumoniae in Scandinavia. The outbreak demonstrates the epidemic potential of enterobacteria containing ESBLs of the CTX-M type, even in a country with a relatively low selective pressure and a low prevalence of multiresistant bacteria. [source] Evaluation of DNA Mixtures from Database SearchBIOMETRICS, Issue 1 2010Yuk-Ka Chung Summary With the aim of bridging the gap between DNA mixture analysis and DNA database search, a novel approach is proposed to evaluate the forensic evidence of DNA mixtures when the suspect is identified by the search of a database of DNA profiles. General formulae are developed for the calculation of the likelihood ratio for a two-person mixture under general situations including multiple matches and imperfect evidence. The influence of the prior probabilities on the weight of evidence under the scenario of multiple matches is demonstrated by a numerical example based on Hong Kong data. Our approach is shown to be capable of presenting the forensic evidence of DNA mixtures in a comprehensive way when the suspect is identified through database search. [source] The DNA Database Search Controversy Revisited: Bridging the Bayesian,Frequentist GapBIOMETRICS, Issue 3 2007Geir Storvik Summary Two different quantities have been suggested for quantification of evidence in cases where a suspect is found by a search through a database of DNA profiles. The likelihood ratio, typically motivated from a Bayesian setting, is preferred by most experts in the field. The so-called np rule has been suggested through frequentist arguments and has been suggested by the American National Research Council and Stockmarr (1999, Biometrics55, 671,677). The two quantities differ substantially and have given rise to the DNA database search controversy. Although several authors have criticized the different approaches, a full explanation of why these differences appear is still lacking. In this article we show that a P-value in a frequentist hypothesis setting is approximately equal to the result of the np rule. We argue, however, that a more reasonable procedure in this case is to use conditional testing, in which case a P-value directly related to posterior probabilities and the likelihood ratio is obtained. This way of viewing the problem bridges the gap between the Bayesian and frequentist approaches. At the same time it indicates that the np rule should not be used to quantify evidence. [source] | ||||||||||||||||