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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
61

Die Haplotypisierung des Y-Chromosoms

Roewer, Lutz 26 June 2001 (has links)
Haploid vererbte Polymorphismen des Y-Chromosoms sind wichtige diagnostische Werkzeuge der forensischen Genetik und verwandter Disziplinen, insbesondere der Anthropologie. Geschlechtsspezifität und uniparentaler Erbgang der Merkmale ermöglichen eine Reihe von Untersuchungen, die mit autosomalen Markern erfolglos bleiben müssen. Kurze tandem-repetitive STR-Sequenzen, die polymorphen Marker der Wahl im forensischen Labor, sind auch auf dem Y-Chromosom nachzuweisen. Aufgrund der rekombinationsfreien, paternalen Vererbung des größten Teils des Y-Chromosoms werden locus-spezifische Allele hier en bloc, als hochinformativer Haplotyp, vererbt. Die forensische Untersuchung profitiert insbesondere auf dem Gebiet der Untersuchung biologischer Spuren von der Y-chromosomalen Diagnostik: vor allem in Vergewaltigungsfällen kann die männliche DNA-Fraktion der Abstrichpräparate unabhängig von der weiblichen des Opfers untersucht und individualisiert werden. Bei der Abstammungsuntersuchung wird in solchen Fällen die Y-chromosomale Analyse empfohlen, in denen der Vater (eines männlichen Kindes) nicht zur Verfügung steht und paternale Verwandte an seiner statt untersucht werden müssen. Von den 14 evaluierten Y-chromosomalen STR-Systemen sind 9 für die forensische Praxis ausgewählt und empfohlen worden. Sie bilden den sogenannten "minimal haplotype", der heute international für die o. g. Analysen verwendet und von der zuständigen Fachgesellschaft (International Society of Forensic Genetics) in ihren Richtlinien empfohlen wird. Wegen der immensen Haplotyp-Variabilität und des uniparentalen Erbgangs ist die Frequenzbestimmung, und damit die Entscheidungsfindung für rechtsmedizinische Gutachter, nur über den Zugang zu großen Datenbanken möglich. Zu diesem Zweck wurde an der Charité die "European Y-STR Haplotype Reference Database" eingerichtet, die Frequenzabfragen auf Grundlage des aktuellen Datenmaterials online ermöglicht (http://ystr.charite.de). Aufgrund des uniparentalen Erbmodus und der im Vergleich zu Autosomen verringerten effektiven Zahl von Y-Chromosomen in der Population muß mit einem meßbaren Einfluß genetischer Drift auf die Y-STR-Haplotyp-Verteilung in der Population gerechnet werden. Mit Hilfe der AMOVA (Analysis of Molecular Variance) - Methode konnten genetische Distanzen für eine repräsentative Auswahl von über 50 weltweit verteilter Populationen berechnet werden. Der AMOVA-Test ist unentbehrlich für die Überprüfung der Eignung von Referenzdatenbanken als Grundlage der Frequenzbestimmung von Y-STR-Haplotypen. / There are a number of merits that qualify the Y chromosome as a special forensic genetic tool: the male specificity for most of its length, the absence of recombination which provides unambiguous male lineage's and the small effective population size that tends to create population specific allele distributions of the Y chromosomes. Particularly in cases of rape and other sexual assault as well as in kinship testing, Y-STR haplotyping can help to close informativity gaps. Since the main goal of forensic genetics is individualization of persons or lineages of descent an analytical strategy for the male chromosome must enable the expert to differentiate between the majority of unrelated haplotypes. For this to achieve the choice of the sequence type and its variability (i.e. its mutation rate) as well as the number of individual sequences to be used for profiling is crucial. We have introduced a STR profile for the Y-chromosome consisting of 11 microsatellite sequences which is both informative for individualization purposes as well as for a genetic distance analysis of populations. The technical simplicity of the approach led to a rapid introduction of the technique in many of the forensic labs world-wide. Intense international collaboration facilitates the generation of large haplotype reference databases, most of them are online available and searchable (Europe: http://ystr.charite.de and USA: http://www.ystr.org/usa/). By use of haplotype specific parameters such as the molecular distance (which equals the minimum number of mutational steps separating two haplotypes) and the largest available haplotype databases a Bayesian approach to evaluate Y-STR haplotype matches has been proposed. Directly inspired by our work are the recommendations of the International Society of Forensic Genetics (ISFG). These guidelines state some basic principles on forensic analysis using Y-STR polymorphisms: the use of sequenced allelic ladders, the application of a repeat-based nomenclature and the use of suitable haplotype reference databases for statistical evaluation of matches. Still a matter of research , but of the utmost interest is the potential of the Y-chromosome analysis to unravel the ethnological background of a given male profile. A dual approach - that using Y-STRs as well as Y-SNPs - probably renders the maximum amount of information about the descent of a male lineage typed in a forensic specimen.
62

Diversitat genòmica a les poblacions del Nord d'Àfrica

Bosch Fusté, Elena 18 February 2000 (has links)
S'ha estudiat la variabilitat genètica de les poblacions del nord d'Àfrica a partir de l'anàlisi de diverses regions genòmiques per tal d'entendre les poblacions analitzades d'una banda, i comprendre la dinàmica del genoma per l'altra. Els resultats obtinguts ens han permès verificar diferents hipòtesis sobre la història de les poblacions d'aquesta regió com són l'efecte paral·lel i independent de l'onada de difusió del neolític des de l'Orient Mitjà al llarg d'ambdues ribes de la Mediterrànea; i l'efecte de l'arabització. S'ha pogut estimar també la contribució genètica masculina nord africana a la península ibèrica i detectat certa contribució genètica del pobles sub-saharians a les poblacions nordafricanes. Per altra banda, el tipatge de marcadors genètics que evolucionen a velocitats diferents al cromosoma Y ha permès mostrar que el background genètic predomina sobre el background poblacional en l'estructura de la variació genètica dels microsatèl·lits en la regió no recombinant del cromosoma Y humà. / The genetic variability of the North African populations has been studied through the analysis of different genomic regions in order to understand both the analysed populations and the dynamics of the genome. The obtained results allow us to verify different hypotheses about the population history of this region including the parallel and independent effect of the Neolithic wave of advance from the Middle East and along both Mediterranean coasts; and the effect of Arabization phenomena. We also tried to estimate the North African male genetic contribution to the Iberian peninsula and detected Sub-Saharian genetic influences to the North African peoples. Moreover, the typing of genetic markers with different evolutionary rates on the Y chromosome allowed us to demonstrate that variation in microsatellites is deeply structured by genetic background on the non-recombining region of the human Y chromosome.
63

Polimorfismos de inserção/deleção no cromossomo X: análise de 32 marcadores na população do estado de São Paulo (Brasil) / X chromosome insertion/deletion polymorphisms: analysis of 32 markers in São Paulo state population (Brazil)

Martinez, Juliana 30 November 2017 (has links)
Submitted by JULIANA MARTINEZ null (jumrtz@hotmail.com) on 2018-01-30T20:15:12Z No. of bitstreams: 1 Tese de Doutorado - Juliana Martinez_versaofinal.pdf: 5281561 bytes, checksum: 3904c01cc47c8b76f9c22a3a88eeb574 (MD5) / Approved for entry into archive by Maria Irani Coito null (irani@fcfar.unesp.br) on 2018-02-02T16:30:55Z (GMT) No. of bitstreams: 1 martinez_j_dr_arafcf_int.pdf: 5281561 bytes, checksum: 3904c01cc47c8b76f9c22a3a88eeb574 (MD5) / Made available in DSpace on 2018-02-02T16:30:55Z (GMT). No. of bitstreams: 1 martinez_j_dr_arafcf_int.pdf: 5281561 bytes, checksum: 3904c01cc47c8b76f9c22a3a88eeb574 (MD5) Previous issue date: 2017-11-30 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Na rotina da genética forense, o uso exclusivo dos marcadores STRs (Short Tandem Repeats) em situações que a amostra biológica apresenta-se degradada pode gerar um resultado final estatístico inconclusivo, tornando fundamental a análise de marcadores adicionais para a resolução do caso. Utilizado como método complementar, os polimorfismos InDels (inserção/deleção) têm mostrado grande potencial para superar as limitações dos marcadores tradicionais. A análise de regiões do cromossomo X também vem ganhando significativa importância nesses estudos, especialmente nos casos em que a análise dos autossômicos não é suficiente. Nessa perspectiva, este trabalho teve por objetivo geral caracterizar a população do estado de São Paulo para 32 polimorfismos de inserção/deleção no cromossomo X (32 X-InDels) e avaliar a utilidade desse multiplex na resolução de casos forenses. Para tanto, buscou-se identificar a diversidade genética desses polimorfismos nessa população, a segregação dos alelos entre os genitores (pai e mãe) para as suas respectivas filhas e a eficiência desse painel na amplificação de DNA extraído de amostras ósseas. Para identificar a diversidade genética, foram analisados os perfis genotípicos de 500 indivíduos não aparentados nascidos no estado de São Paulo. Todos os marcadores mostraram-se polimórficos para a população, sendo MID3701 o que apresentou maior diversidade e somente MID2637 se mostrou pouco informativo. O marcador MID1361 apresentou-se em desequilíbrio de Hardy-Weinberg e uma variante alélica foi identificada em seu alelo curto. O painel demonstrou alta eficiência forense, confirmado pelo poder acumulado de discriminação (0,999999999993 em mulheres e 0,99999993 em homens) e pelo valor acumulado da chance média de exclusão (0,999996 em trios e 0,9995 em duos). No comparativo com outras populações, valores significativos da distancia genética foram obtidos, verificando-se que São Paulo está mais próximo à três departamentos colombianos e às populações européias. A proporção de ancestralidade identificada foi 41,8% para europeus, 31,6% para africanos e 26,6% para nativo-americanos. Na análise de segregação realizada em 101 trios, o padrão de transmissão esperado entre pai-mãe/filha foi o observado, o que confirma a baixa taxa de mutação desses marcadores. Por fim, os 32 X-InDels apresentaram as características necessárias para a análise de amostras biológicas em baixa concentração e/ou degradadas, mas algumas dificuldades na amplificação podem ser encontradas a depender das condições ambientais a que as amostras foram expostas. Conclui-se que o conhecimento acerca dos marcadores de inserção/deleção no cromossomo X pode ser ampliado, uma vez que na literatura ainda há pouco material disponível sobre o assunto; entretanto os dados deste trabalho já demonstram seu potencial como método alternativo para a análise de amostras forenses, pois foram identificados elevados valores de poder de discriminação e exclusão, baixa taxa de mutação e um elevado potencial de amplificação de amostras biológicas degradadas. / In forensic genetics routine, the exclusive use of STRs (Short Tandem Repeats) markers when the biological sample is degraded can generate an inconclusive final statistical result, making essential the analysis of additional markers for case resolution. Used as a complementary method, InDels (insertion/deletion) polymorphisms have shown great potential to overcome the limitations of traditional markers. Polymorphisms in the X chromosome is also gaining significant importance in these studies, especially in those cases in which the analysis of the autosomal markers is not enough. In this perspective, this study aimed to characterize the São Paulo state population for 32 X chromosome insertion/deletion polymorphisms (32 X-InDels) and to evaluate the utility of this multiplex in the resolution of forensic cases. Therefore, it was analyzed the genetic diversity of this population, the alleles segregation between the parents and their respective daughters, and the amplification efficiency of this panel in DNA extracted from human bones. To identify genetic diversity, the genotypic profiles of 500 unrelated individuals born in São Paulo state was analysed. All markers were polymorphic for the population, with MID3701 being the most diverse, and MID2637 the less informative. The MID1361 marker was in Hardy-Weinberg disequilibrium and an allelic variant was identified in its short allele. The panel showed high forensic efficiency, confirmed by the accumulated power of discrimination (0.9999999999993 in females and 0.99999993 in males) and by the accumulated mean exclusion chance (0.999996 in trios and 0.99995 in duos). Comparing with other populations, significant values of genetic distance were obtained and São Paulo is closer to three Colombian departments and to European populations. The ethnic contributions identified 41.8% of Europeans, 31.6% of Africans and 26.6% of Native Americans admixture. In segregation analysis performed in 101 trios, the expected transmission pattern between parent/daughter was observed, which confirms the low mutation rate of these markers. Finally, the 32 X-InDels presented the necessary characteristics for the analysis of degraded biological samples, but some amplification difficulties can be found depending on the environmental conditions in which the samples were exposed. It can be concluded that knowledge about the X chromosome insertion/deletion markers can be expanded, because there is still little information available in the literature; meanwhile data from this work demonstrate its potential as an alternative method for the analysis of forensic samples.
64

Engenharia forense: estudo de microvestígios coletados em locais de crime (touch DNA) / Forensic engineering: study of collected microtraces in crime locations (touch DNA)

Barbosa, Carlos de Almeida 03 February 2017 (has links)
As últimas décadas trouxeram grandes avanços tecnológicos às ciências forenses. Um dos marcos dessa evolução foram às pesquisas e os resultados obtidos com a aplicação da Biologia Molecular, como ferramenta de identificação humana a partir da década de 80. Desde então, novos estudos vêm sendo realizados nesta área. Vestígios encontrados em locais de crime são elementos que irão orientar na busca pela elucidação dos fatos. Existem dois tipos de vestígios: os macrovestígios, facilmente identificados e os microvestígios que demandam análises técnicas mais específicas. Dentre os microvestígios, tem-se a impressão digital, que se tornou uma possível fonte de extração de DNA, com um grande potencial de recuperação do material genético. Este trabalho objetivou analisar amostras coletadas em microvestígios de impressões digitais em vários objetos escolhidos como superfície de deposição sendo elas, vidro, metal, plástico, madeira e parede de alvenaria, demonstrando que é possível estabelecer uma ligação entre as amostras de DNA e as impressões digitais encontradas. As amostras foram coletadas de impressões latentes intactas e em esfregaço e impressões digitais intactas e em esfregaço com pó. Os resultados demonstraram a viabilidade de utilização deste tipo de amostra, tendo em vista a recuperação de DNA e o êxito da genotipagem. Os resultados obtidos nas diferentes matrizes analisadas evidenciaram maior êxito na superfície de metal, onde foi possível obter perfil genético íntegro em todas as amostras coletadas e analisadas. Com relação à matriz vidro, nas amostras “intacta latente” e “esfregaço latente” foi possível recuperar perfil genético com mais de 17 locos amplificados. Já nas amostras “intactas e esfregaço com pó”, mesmo com a confirmação da presença de DNA, as quantidades recuperadas foram insuficientes para gerar o eletroferograma. Na matriz madeira, assim como na matriz plástico, foi constatada a presença de DNA, mas em baixa concentração para gerar o eletroferograma. E, por último, as amostras coletadas da matriz parede de alvenaria “intacta latente” e “intacta com pó”, apresentaram respectivamente amplificação de 17 e 19 locos dos 24 presentes no kit. Estudos e experimentos já tornaram esta metodologia viável no Laboratório de Genética Molecular Forense da Polícia Científica do Estado do Paraná, com resultados positivos em diversos casos, identificando suspeitos e contribuindo com a Rede Integrada de Banco de Perfis Genéticos (RIBPG). Os resultados demonstraram a eficiência e a possibilidade de se obter um perfil genético quando se trabalha com este tipo de amostra, tornando esta mais uma ferramenta pericial. / The last decades have brought great technological advances to the Forensic Sciences. The Molecular Biology has been used as a tool for human identification since the 80´s, and it has bought fantastic results from this application, being a landmark in the evolution of Forensic Science. Since this decade, new studies have been carried out in this area. Traces found in crime scenes are elements that can guide the search for the elucidation of the facts. There are two types of traces: macro-traces, that are easily identified and micro-traces that requires more specific technical analysis. One of the traces is the digital fingerprint, that is a possible source of DNA extraction, with great potential for recovery of the genetic material. This research has the purpose to analyze samples collected from fingerprints on various objects chosen as deposition surface, such as glass, metal, plastic, wood and masonry wall. This research shows that it is possible to establish a connection between DNA samples and fingerprints. Samples have been collected from intact and intact smears and fingerprints intact and smeared with powder. The results showed the feasibility of using this type of sample, based on the DNA recovery and the success of the genotyping. The results obtained in the different matrices analyzed showed greater results in the metal surface, where it was possible to obtain a complete genetic profile in all the samples Collected and analyzed. In the glass matrix, either the samples "latent intact" or in "latent smear" it was possible to recover genetic profile with more than 17 amplified loci. In the "intact and powder smear" samples, even with confirmation of the presence of DNA, the quantities recovered were insufficient to generate the electropherogram. In the wood matrix, such as in the plastic matrix, the presence of DNA was observed, but at low concentration to generate the electropherogram. Finally, the samples collected from the "latent intact" and "intact with powder" masonry wall samples, respectively, showed amplification of 17 and 19 loci of the 24 present in the kit. Some Studies and experiments have been done in the Forensic Molecular Genetics Laboratory of Scientific Police in Paraná with positive results in many cases, identifying suspects and contributing to the Integrated Network of Gene Prolifiling Banks (RIBPG). These studies have made this methodology feasible. The results show the efficiency and the possibility of obtaining a genetic profile from this type of sample, making this one more important pericial tool.
65

Engenharia forense: estudo de microvestígios coletados em locais de crime (touch DNA) / Forensic engineering: study of collected microtraces in crime locations (touch DNA)

Barbosa, Carlos de Almeida 03 February 2017 (has links)
As últimas décadas trouxeram grandes avanços tecnológicos às ciências forenses. Um dos marcos dessa evolução foram às pesquisas e os resultados obtidos com a aplicação da Biologia Molecular, como ferramenta de identificação humana a partir da década de 80. Desde então, novos estudos vêm sendo realizados nesta área. Vestígios encontrados em locais de crime são elementos que irão orientar na busca pela elucidação dos fatos. Existem dois tipos de vestígios: os macrovestígios, facilmente identificados e os microvestígios que demandam análises técnicas mais específicas. Dentre os microvestígios, tem-se a impressão digital, que se tornou uma possível fonte de extração de DNA, com um grande potencial de recuperação do material genético. Este trabalho objetivou analisar amostras coletadas em microvestígios de impressões digitais em vários objetos escolhidos como superfície de deposição sendo elas, vidro, metal, plástico, madeira e parede de alvenaria, demonstrando que é possível estabelecer uma ligação entre as amostras de DNA e as impressões digitais encontradas. As amostras foram coletadas de impressões latentes intactas e em esfregaço e impressões digitais intactas e em esfregaço com pó. Os resultados demonstraram a viabilidade de utilização deste tipo de amostra, tendo em vista a recuperação de DNA e o êxito da genotipagem. Os resultados obtidos nas diferentes matrizes analisadas evidenciaram maior êxito na superfície de metal, onde foi possível obter perfil genético íntegro em todas as amostras coletadas e analisadas. Com relação à matriz vidro, nas amostras “intacta latente” e “esfregaço latente” foi possível recuperar perfil genético com mais de 17 locos amplificados. Já nas amostras “intactas e esfregaço com pó”, mesmo com a confirmação da presença de DNA, as quantidades recuperadas foram insuficientes para gerar o eletroferograma. Na matriz madeira, assim como na matriz plástico, foi constatada a presença de DNA, mas em baixa concentração para gerar o eletroferograma. E, por último, as amostras coletadas da matriz parede de alvenaria “intacta latente” e “intacta com pó”, apresentaram respectivamente amplificação de 17 e 19 locos dos 24 presentes no kit. Estudos e experimentos já tornaram esta metodologia viável no Laboratório de Genética Molecular Forense da Polícia Científica do Estado do Paraná, com resultados positivos em diversos casos, identificando suspeitos e contribuindo com a Rede Integrada de Banco de Perfis Genéticos (RIBPG). Os resultados demonstraram a eficiência e a possibilidade de se obter um perfil genético quando se trabalha com este tipo de amostra, tornando esta mais uma ferramenta pericial. / The last decades have brought great technological advances to the Forensic Sciences. The Molecular Biology has been used as a tool for human identification since the 80´s, and it has bought fantastic results from this application, being a landmark in the evolution of Forensic Science. Since this decade, new studies have been carried out in this area. Traces found in crime scenes are elements that can guide the search for the elucidation of the facts. There are two types of traces: macro-traces, that are easily identified and micro-traces that requires more specific technical analysis. One of the traces is the digital fingerprint, that is a possible source of DNA extraction, with great potential for recovery of the genetic material. This research has the purpose to analyze samples collected from fingerprints on various objects chosen as deposition surface, such as glass, metal, plastic, wood and masonry wall. This research shows that it is possible to establish a connection between DNA samples and fingerprints. Samples have been collected from intact and intact smears and fingerprints intact and smeared with powder. The results showed the feasibility of using this type of sample, based on the DNA recovery and the success of the genotyping. The results obtained in the different matrices analyzed showed greater results in the metal surface, where it was possible to obtain a complete genetic profile in all the samples Collected and analyzed. In the glass matrix, either the samples "latent intact" or in "latent smear" it was possible to recover genetic profile with more than 17 amplified loci. In the "intact and powder smear" samples, even with confirmation of the presence of DNA, the quantities recovered were insufficient to generate the electropherogram. In the wood matrix, such as in the plastic matrix, the presence of DNA was observed, but at low concentration to generate the electropherogram. Finally, the samples collected from the "latent intact" and "intact with powder" masonry wall samples, respectively, showed amplification of 17 and 19 loci of the 24 present in the kit. Some Studies and experiments have been done in the Forensic Molecular Genetics Laboratory of Scientific Police in Paraná with positive results in many cases, identifying suspects and contributing to the Integrated Network of Gene Prolifiling Banks (RIBPG). These studies have made this methodology feasible. The results show the efficiency and the possibility of obtaining a genetic profile from this type of sample, making this one more important pericial tool.
66

Statistical and computational methodology for the analysis of forensic DNA mixtures with artefacts

Graversen, Therese January 2014 (has links)
This thesis proposes and discusses a statistical model for interpreting forensic DNA mixtures. We develop methods for estimation of model parameters and assessing the uncertainty of the estimated quantities. Further, we discuss how to interpret the mixture in terms of predicting the set of contributors. We emphasise the importance of challenging any interpretation of a particular mixture, and for this purpose we develop a set of diagnostic tools that can be used in assessing the adequacy of the model to the data at hand as well as in a systematic validation of the model on experimental data. An important feature of this work is that all methodology is developed entirely within the framework of the adopted model, ensuring a transparent and consistent analysis. To overcome the challenge that lies in handling the large state space for DNA profiles, we propose a representation of a genotype that exhibits a Markov structure. Further, we develop methods for efficient and exact computation in a Bayesian network. An implementation of the model and methodology is available through the R package DNAmixtures.
67

Blood on FTA™ Paper: Does Punch Location Affect the Quality of a Forensic DNA Profile?

Carter, Megan Elizabeth 06 March 2013 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / Forensic DNA profiling is widely used as an identification tool for associating an individual with evidence of a crime. Analysis of a DNA sample involves observation of data in the form of an electropherogram, and subsequently annotating a DNA “profile” from an individual or from the evidence. The profile obtained from the evidence can be compared to reference profiles deposited in a national DNA database, which may include the potential contributor. Following a match, a random match probability is calculated to determine how common that genotype is in the population. This is the probability of obtaining that same DNA profile by sampling from a pool of unrelated individuals. Each state has adopted various laws requiring suspects and/or offenders to submit a DNA sample for the national database (such as California’s law that all who are arrested must provide a DNA sample). These profiles can then be associated with past unsolved crimes, and remain in the database to be searched in the event of future crimes. In the case of database samples, a physical sample of the offender’s DNA must be kept on file in the laboratory indefinitely so that in the event of a database hit, the sample is able to be retested. Current methods are to collect a buccal swab or blood sample, and store the DNA extracts under strict preservation conditions, i.e. cold storage, typically -20° C. With continually increasing number of samples submitted, a burden is placed on crime labs to store these DNA extracts. A solution was required to help control the costs of properly storing the samples. FTA™ paper was created to fulfill the need for inexpensive, low maintenance, long term storage of biological samples, which makes it ideal for use with convicted offender DNA samples. FTA™ paper is a commercially produced, chemically treated paper that allows DNA to be stored at room temperature for years with no costly storage facilities or conditions. Once a sample is required for DNA testing, a small disc is removed and is to be used directly in a PCR reaction. A high quality profile is important for comparing suspect profiles to unknown or database profiles. A single difference between a suspect and evidentiary sample can lead to exclusion. Unfortunately, the DNA profile results yielded from the direct addition have been unfavorable. Thus, most crime laboratories will extract the DNA from the disc, leading to additional time and cost to analyze a reference sample. Many of the profiles from the direct addition of an FTA™ disc result in poor quality profiles, likely due to an increase in PCR inhibitors and high concentrations of DNA. Currently, standardized protocols regarding the recommended locations for removal of a sample disc from a bloodspot on an FTA™ card does not exist. This study aims to validate the optimal location by comparing DNA profiles obtained from discs removed from the center, halfway, and edge locations of a bloodspot from 50 anonymous donors. Optimal punch location was first scored on the number of failed, partial or discordant profiles. Then, profile quality was determined based on peak characteristics of the resulting DNA profiles. The results for all three disc locations were 5.3% failed amplifications, 4.2% partial amplifications, and one case of a discordant profile. Profile quality for the majority of the samples showed a high incidence of stutter and the absence of non-template adenylation. Of the three disc locations, the edge of the blood stain was ideal, due to a presumably lower concentration of DNA and likely more dilute amount of the PCR inhibitor heme. Therefore, based on the results of this study, there is a greater probability of success using a sample from the edge of a blood stain spotted in FTA™ paper than any other location of the FTA™ card.
68

An evaluation of the management of deoxyrinucleic acid (DNA) evidence / An evaluation of the management of deoxyribonucleic acid (DNA) evidence

Dywaba, Zukiswa Morencia 09 1900 (has links)
DNA is identified as a powerful tool in the solving of rape cases, but it is often destroyed either by members of the public or the police officials who attend to the scene. The aim of the study was to evaluate the management of DNA evidence in rape cases in the Bishop Lavis Policing Area. To address the research topic under investigation, research questions, a legal framework and policies were used. The outcome of the study indicated poor performance in securing the crime scene and ensuring that physical evidence is preserved and not tampered with. On this basis, it was recommended that developmental workshops and intensive training on the management of DNA evidence be conducted to all members of the South African Police Service attend to rape crime scenes. This should be done to equip them with knowledge and an understanding of the management of DNA evidence. / Police Practice / M. Tech. (Forensic Investigation)
69

Modelagem de um ambiente para análise de DNA em genética forense

Sarmento, Felipe José de Queiroz 12 May 2006 (has links)
The advances in molecular biology have increased the production of enormous amount of genetic information in a small period of time. This capacity of data production motivated the researchers to increase the rhythm of their researches. This necessity demands the use of efficient softwares in order to manage these data. Besides this, it also demands the development of good softwares in order to assist the researchers in the task of analyzing the data and giving them a biological meaning in a brief space of time. This work proposes a software model that will support the study of Forensic DNA, whose main repository is the autossomic DNA. This software intends to support the researchers in the identification of condemned persons or persons that are suspected of a crime. It also intends to assist the researchers in the study of paternity and the search for disappeared persons. The results of this work will be applied in the Forensic DNA Laboratory of UFAL. The software modeled here has four modules study of paternity , criminal , disappeared people and the bank of populational frequencies . The modules were modeled independently from each other, considering the specifications related to the analysis of genetic links. The software was developed using the JAVA programming language together with PostgreSQL database. Both are free software and have an excellent relationship between cost and benefit usage / Fundação de Amparo a Pesquisa do Estado de Alagoas / Os avanços da biologia molecular vêm favorecendo a geração de uma enorme quantidade de informações genéticas em um tempo cada vez menor. Essa capacidade de geração de dados permite que os pesquisadores acelerem o ritmo de suas pesquisas, exigindo a utilização de ferramentas eficientes para o gerenciamento desses dados. Outra necessidade está relacionada com o desenvolvimento de ferramentas computacionais com capacidade de auxiliar na tarefa de análisar e dar um significado biológico a estes dados em um breve espaço de tempo para os pesquisadores. Este trabalho propõe a modelagem de um ambiente de apoio à análise e ao estudo do DNA Forense, cujo principal repositório seja o DNA autossômico. Este ambiente visa dar suporte a identificação de pessoas condenadas ou suspeitas de ter realizado algum tipo de crime contra a sociedade, bem como auxiliar no estudo de paternidade e na busca de pessoas desaparecidas. Este ambiente irá atender ao Laboratório de DNA Forense, da UFAL, que vêm realizando estas atividades. O modelo do ambiente aqui proposto, possui quatro módulos, estudo de paternidade , criminal , desaparecido e o banco de freqüência das populações . Os módulos foram modelados de forma que funcionem independentemente, atendendo as especificações inerentes à análise sobre vínculo genético. O sistema foi desenvolvido na linguagem de programação JAVA com banco de dados PostgreSQL. Ambas as ferramentas possuem característica de software aberto e uma relação custo/benefício excelentes
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Evaluation of the IrisPlex DNA-based eye color prediction tool in the United States

Dembinski, Gina M. 31 July 2014 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / DNA phenotyping is a rapidly developing area of research in forensic biology. Externally visible characteristics (EVCs) can be determined based on genotype data, specifically from single nucleotide polymorphisms (SNPs). These SNPs are chosen based on their association with genes related to the phenotypic expression of interest, with known examples in eye, hair, and skin color traits. DNA phenotyping has forensic importance when unknown biological samples at a crime scene do not result in a criminal database hit; a phenotype profile of the sample can therefore be used to develop investigational leads. IrisPlex, an eye color prediction assay, has previously shown high prediction rates for blue and brown eye color in a European population. The objective of this work was to evaluate its utility in a North American population. We evaluated the six SNPs included in the IrisPlex assay in an admixed population sample collected from a U.S.A. college campus. We used a quantitative method of eye color classification based on (RGB) color components of digital photographs of the eye taken from each study volunteer and placed in one of three eye color categories: brown, intermediate, and blue. Objective color classification was shown to correlate with basic human visual determination making it a feasible option for use in future prediction assay development. In the original IrisPlex study with the Dutch samples, they correct prediction rates achieved were 91.6% for blue eye color and 87.5% for brown eye color. No intermediate eyes were tested. Using these samples and various models, the maximum prediction accuracies of the IrisPlex system achieved was 93% and 33% correct brown and blue eye color predictions, respectively, and 11% for intermediate eye colors. The differences in prediction accuracies is attributed to the genetic differences in allele frequencies within the sample populations tested. Future developments should include incorporation of additional informative SNPs, specifically related to the intermediate eye color, and we recommend the use of a Bayesian approach as a prediction model as likelihood ratios can be determined for reporting purposes.

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