Browsing by Subject "Computational Biology"
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Item A Novel sRNA Member of the Carbon Storage Regulatory System of Escherichia Coli(2002-12-01) Weilbacher, Thomas; Jerry SimeckaWeilbacher, Thomas S., A Novel sRNA Member of the Carbon Storage Regulatory System of Escherichi coli. Master of Science (Microbiology & Immunology), December, 2002, 57 pp., 2 tables, 12 illustrations, bibliography, 44 titles. Small untranslated RNAs (sRNAs) perform a variety of important functions in bacterial systems. The 245 nt sRNA of Escherichia coli K-12, CsrC, was uncovered using a genetic screen for genes that regulate glycogen biosynthesis. CsrC RNA binds multiple copies of CsrA, a protein that post-transcriptionally regulates central carbon flux, biofilm formation, and motility in E. coli. CsrC antagonizes the regulatory effects of CsrA, presumably by sequestering this protein. The discovery of CsrC is intriguing, in that a similar sRNA, CsrB, performs essentially the same function. Both of these sRNAs possess similar imperfect repeat sequences (18 in CsrB, 9 in CsrC), primarily localized in the loops of predicted hairpins, which may serve as CsrA binding elements. Transcription of csrC increases as the culture approaches the stationary phase of growth and is activated by CsrA and the response regulator UvrY. Complementation and in vitro transcription-translation experiments reveal that CsrA effects on csrC are mediated indirectly, through UvrY. Because CsrB and CsrC antagonize the activity of CsrA and are dependent on CsrA for their synthesis, a csrB null mutation causes a modest compensatory increase in CsrC levels and vice versa. An updated model for the signaling circuitry of the Csr system is discussed.Item A Study of the Efficiency of the Combined DNA Index System for the Oregon State Police(2007-08-01) Brown, Allison A.; Joseph Warren; Arthur Eisenberg; John PlanzMethod of Procedure: This project, which was conducted at the Oregon State Police Crime Laboratory, entailed following up with CODIS hits. It involved examining cases that have been worked by forensic scientists and finding explanations as to how the cases are proceeding after NDA matches are made. Failures to follow up on a CODIS hit have become a national problem in forensic laboratories all over the country. The Oregon State Police find this a very important issue that must be resolved. Currently the Oregon State Police are getting a hit, an arrest and a conviction. The only problem with all of this is that it is hard to measure the efficiency of CODIS hits with just convictions. There are several ways the cases could have been resolved such as the victim did not want to pursue the case any further, the suspect was already incarcerated for another crime, the witnesses were hard to locate or the case was dropped because of a plea to other crimes. As part of my research I investigated each of the cases that have been worked to see if they were pursued any further after a hit to an individual. After researching these cases, it was my responsibility to put my findings into a format that made it easier for the state police to know how the cases were resolved. The information was collected using a variety of software programs. The reason that more then one computer program needed to be used in the project, is due to the fact that more of then not some of the information that should have been provided in a program was absent in one and present in another program. The California Department of Justice currently has a system that is available which allows its users to input data. In order to design such a system it was my responsibility to obtain the case information. Once this had been obtained it made it easier to combine the data into a table format so that the state police could see how each case was proceeding. Below is a table of exactly what information was obtained. Due to the confidentiality of the information, false names and false information will be used in all tables seen. Once the information for one thousand hits had been gathered it was placed into Microsoft Access so that a database could be created. Throughout the time that CODIS has been in place, crimes where DNA matches have been made but not pursued have shed light upon a common problem occurring everywhere in forensic laboratories. Dozens of cases have found matches between a suspect and a crime but there has been no pressure to pursue the case any further. In fact one unfortunate result has been multiple DNA matches of a suspect, with the suspect continuously making repeated offenses. Most of the offenses are nor pursued until the investigators realize there might be a link between the current crime and the past cases worked. Only then are the reports of the DNA matches reviewed and pursued further. In one Virginia case, this scenario occurred. A man by the name of William Orlando Smith followed a girl and raped her in the woods. Had the DNA match that the Virginia police made months earlier been pursued, the rape might have been prevented. This is not just one isolated event but a common occurrence seen in other states as well. Although this research for the Oregon State Police might not resolve a national issue, it will aid in preventing scenarios like the above from possibly occurring. By solving this problem and entering how cases are resolved into a database like Microsoft Access, it will make it easier for the investigators to process crimes. Even more important is the need for this information to be compared with other states. A study such as this will enable states to test the efficiency of CODIS.Item An Initial Comparison of Applied Biosystems Quantifiler Duo and Promega Plexor HY Real-time PCR DNA Quantification Systems(2008-05-01) Cole, Sarah Kathleen; Arthur Eisenberg; John Planz; Joseph WarrenObjective 1: Sensitive Study: This study was designed to determine the quantity of template DNA below which amplification is not expected to yield a DNA profile. Dilution series of male and female stock DNA ranging from 0.003 ng/μl will independently be run with both Quantifiler Duo and Plexor HY. These samples will be run in duplicate per plate, with duplicate plates being run. We want to determine if the published lowest detection thresholds (0.023 ng/μl for Duo; 0.0032 ng/μl for HY) are concordant with the data obtained. Objective 2: Mixture Study: The purpose of this study is to obtain quantification results for mixtures of male and female DNA, which should allow for calculations of autosomal:Y ratios that can be helpful in determining what type of genetic analysis to pursue (autosomal STR, Y-STR, or both). Mixtures of female and male DNA ranging from 1:1 to 1024:1 (female: male) will be run in duplicate per plate, with duplicate plates being run. We want to find out how minor of a contributor the male can be in an excess of female DNA and still be detected. This is especially important in sexual assault cases where the major contributor is usually female or when the offender is a vasectomized male. Objective 3: Concordance Study: The purpose of this study is to compare quantification results from Quantifiler Duo and Plexor HY with those from Quantifiler Human, specifically in cases when samples are degraded. The majority of these samples originate from unidentified human remains. Patterns of overestimation or underestimation of DNA concentration can help determine which system will be most beneficial in these cases. This is where the new amplicons size featured in Quantifiler Duo is important in comparing the values with previous results for Quantifiler Human. Sample choice will be at the discretion of the laboratory technical leader and Unidentified Human Remains section analysts. These samples will be the ones that are known to be degraded and have previously yielded overestimated results from the Quantifiler Human quantification system, resulting in poor STR data.Item Analysis of Low Copy Number DNA Using Profiler Plus at Increased Amplification Cycles and Modifications in Sample Injection Parameters(2003-08-01) Hynds, Jody Lynn; Arthur Eisenberg; John Planz; Joseph WarrenThere are many DNA testing techniques that can be utilized for samples with low quantities of DNA. Mitochondrial DNA testing is designed for successful DNA sequencing of hair shafts, degraded and burned samples. Newly developed SNP (single nucleotide polymorphisms) testing is also designed for the analysis of challenging samples. The increased interest in the analysis of low copy number DNA samples using STR testing is necessitated since the national database CODIS (Combined Data Index System) currently only accepts the DNA profiles analyzed with the 13 core STR loci. CODIS contains DNA profiles of evidence found at crime scenes, convicted offender and missing persons DNA profiles (4). The goal of this project is to develop methodologies to increase the success rate of LCN DNA samples using STR testing. The experimental design for this study involved the amplification of DNA isolated from buccal swabs using the Profiler Plus multiplex kit at two different DNA input quantities: 0/0156ng (15.6pg) and 0.0312ng (31.2pg). Four separate amplifications of these DNA samples were done at: 28, 30, 32 and 34 cycles. The manufacturer’s recommended cycle number for AmpFISTR Profiler Plus is 28 cycles. These samples were analyzed on both the ABI Prism 310 Genetic Analyzer and the ABI Prism 3100 Genetic Analyzer using OCD standard protocols for loading samples. The injection time and voltage were modified for each of the number of PCR cycles. The best combination of cycle number and injection parameters was chosen for the low copy number reproducibility study.Item Beta Testing and the Population Genetics of Promega's Prototype PowerPlex Y Kit(2004-08-01) Kirkendoll, Ross A.; Joseph Warren; John Planz; Arthur EisenbergDevelopmental validation is typically done by the manufacturer of the technique or technology. According to National Standards, the manufacturer must test for human specificity to ensure compliance with standards. In addition, the PowerPlex Y kit must be shown to have male specificity because all of the loci are located on the Y-chromosome. Other necessary studies include mixture both male/female and male/male mixture studies, stability studies to show stability in the presence of environmental insults, and the focus of this study the construction of a popular database. In order to satisfy both the requirement of the National Standards and the scrutiny of the legal system, Promega Corporation assembled a collaboration of different laboratories to assist with the developmental validation of the PowerPlex Y Kit. This project was a small part of that collaboration. The DNA Identify Laboratory was chosen by Promega to assist with the construction of a population database because of the number of samples available and the need for confirmed father/son pairs. The objectives of the study were to type ~200 father/son pairs from each of the Caucasian and African American races, and then determine the haplotype frequencies, haplotype diversities, and mutation rates for each race.Item Changes in Mammalian Chromatin Structure as a Function of Protein-Poly(ADP-Ribosyl)ation by Endonuclease Digestion(2004-06-01) Perez-Lamigueiro, Maria A.; Alvarez, Rafael; Das, Hriday K.; Basu, AlakanandaPerez-Lamiguerio, Maria A., Changes in Mammalian Chromatin Structure as a Function of Protein-poly(ADP-ribosyl)ation by Endonuclease Digestion. Master of Science (Biochemistry and Molecular Biology), June 2004. 66 pages, 12 illustrations, Bibliography, 45 titles. Mammalian chromatin was exposed to either Deoxyribonuclease I or Micrococcal Nuclease digestion as a function of time of incubation and enzyme concentration. Endonuclease enzymatic reactions were stopped with EDTA. Samples were run in 1.5% agarose gels and the oligonucleosomal electrophoretic migration patterns compared. Endonuclease experiments were carried out with rat liver chromatin pre-incubated in the presence or absence of 200 μM βNAD+. A solution of 1.0 mM benzamide was used to stop enzymatic modification. The electrophoretic observations demonstrated a faster and increased degradation of chromatin when proteins were poly(ADP-ribosyl)ated prior to digestion. These results support the hypothesis that that the covalent poly(ADP-ribosyl)ation of chromatin proteins, particularly histones, induces a more relaxed structure, rendering chromatin more sensitive to endonuclease digestion.Item Comparison of DNA Extraction Methods From Bone to be Used With the DNA IQ System on the Maxwell 16 for Human Identification(2008-08-01) Lopez, Kristen; John Planz; Arthur Eisenberg; Joseph WarrenLopez, Kristen M., Comparison of DNA Extraction Methods From Bone to be Used with the DNA IQ System on the Maxwell 16 for Human Identification . Masters of Science (Graduate School of Biomedical Sciences), August, 2008, 52 pp., 11 tables, 15 figures, bibliography, 24 titles. Extraction and purification of DNA from human bones is essential for correctly identifying the remains through DNA analysis. Current DNA extraction methods include a demineralization step, which extracts calcium and phosphate from the bone matrix, inactivation of DNAses, and the removal of Polymerase Chain Reaction (PCR) inhibitors. These methods often use harsh chemicals and may allow for residual DNA to be discarded in various wash steps. To assess the effectiveness of DNA extraction from bone samples, two extraction protocols were compared. The first method included a bone demineralization pretreatment solution of Sodium N-Laurylsarcosinate, 0.5 M EDTA, and Proteinase K (20 mg/ml). The second included a pretreatment using a Bone Incubation Buffer by Promega Corporation, with an addition of Proteinase K (18mg/ml). Various incubation times were included to assess the extraction at different time intervals. All extracted samples were purified with the DNA IQ Reference Sample Kit on the automated Maxwell 16 Instrument (Promega Corp.). Full and partial profiles were obtained from samples extracted with the Bone Incubation pretreatment, regardless of incubation time. Profiles were not observed with the standard demineralization pretreatment when amplified at 28 cycles, with partial profiles present in a few samples when amplified at 32 cycles.Item Comparison of Next Generation Sequencing Methodology on the Ion PGM™ System Performance versus that on the Sanger Sequencing Method for HV1 and HV2 Regions of mtDNA(2015-05-01) Argueta, Wendy C.; Arthur J. Eisenberg; Michael Allen; Raghu R. KrishnamoorthyAnalysis of mitochondrial DNA in forensic applications has enabled the identification of a missing person through comparison with additional maternal relatives. Most forensic applications are based on sequencing of both hypervariable regions of the mtDNA. Sequencing of these regions has been commonly done using Sanger-type sequencing (STS) methodology, which is expensive, time-consuming and laborious. Next Generation Sequencing (NGS) technology, such as the Ion Torrent PGM™ System platform, overcomes most of these issues. In this study, samples from the Guatemalan population (n=40) were sequenced with both Ion Torrent PGM™ technology and STS methods. A high level of consistency (98%) was observed among data derived from both methods. Most of the discrepancies were point heteroplasmy, which were more easily detected by PGM™ technology. In terms of performance, the NGS method was shown to be quick, with high-throughput and more efficient compared to the traditional STS method. More accurate and reliable sequencing data were obtained from the Ion Torrent PGM™ method due to its high level of coverage. Sequencing data for all individuals, representing 19 different family groups, were obtained using the NGS technology. Sequence polymorphisms were detected in 55 positions, from which 26 were observed only in relatives belonging to the same family and were not observed for any other family group. In a forensic context, haplotype specific polymorphisms are the basis for identification and comparison between evidence and reference samples purposes. Haplotypes between maternally related individuals were consistent in 18 family groups.Item Construction of a Cost Effective Nested-PCR Reaction for Use with the Applied Biosystems AmpFLSTR Identifiler Kit(2005-12-01) Mikeska, Margo M.; John Planz; Joseph Warren; Arthur EisenbergHuman STR analysis has greatly increased the ability to perform identity testing for many different situations. These situations include, but are not limited to, the identification of individuals involved in violent crimes, establishing paternity, and identification of unknown human remains. The most common type of DNA information currently used for identity testing is the short tandem repeat, or STR. STR testing utilizes the number of repeating units in the DNA to assign an allele. Alleles from several different loci are used to establish a genetic profile. Currently, the United States used a standard of 13 different DNA loci to establish identity. These 13 loci can be typed by using a number of different multiplex kits such as the Applied Biosystems Profiler Plus, Cofiler, and Identifiler Kits [1,2]. The 13 loci were selected based on a number of parameters. Each locus was required to be polymorphyic, and a tetranucleotide repeat. The loci also could not display any linkage between each other and extensive population studies had to be conducted to both verify the absence of linkage and to establish allelic frequencies [1]. The goal of this research was the construction of a more cost effective method of utilizing the Applied Biosystems Identifiler Kit. Across the country there is a large backlog of samples that need to be processed in order to obtain a genetic profile. If these samples could be tested using a more cost effective method, more funding could be directed to other endeavors. Paternity testing, as well as some research endeavors could be conducted at a fraction of the cost, leaving resources for other projects or additional staff. Although it would be inadvisable to use this technique on forensic samples, the implications on paternity and research samples would be positive. This research attempted to design a nested PCR reaction and subsequently dilute the Applied Biosystems Primers in order to reduce the cost. The first step was to design new primers for the first round of PCR, followed by testing of those primers. The new primers then required optimization so that they all worked effectively together. After optimization was accomplished, the Identifiler primers were diluted until loci began dropping out of the genetic profile.Item Development of a Comprehensive Massively Parallel Sequencing Panel of Single Nucleotide Polymorphism and Short Tandem Repeat Markers for Human Identification(2015-08-01) Warshauer, David H.; Bruce Budowle; Ranajit Chakraborty; Bobby L. LaRueMassively parallel sequencing (MPS) technologies allow for the detection of an unparalleled amount of genetic information with unprecedented speed and relative ease. These qualities make the technology desirable for generating DNA profiles that may be uploaded into forensic offender, arrestee, and family reference database files. This doctoral dissertation research was conducted under the hypothesis that MPS, with its exquisitely high throughput, can provide a system whereby reference samples can be typed for a large battery of markers, providing more discrimination power for forensic DNA typing and offering increased opportunities to develop investigative leads. The design and implementation of large marker panels for the typing of reference samples will reduce debates on the best core markers for forensic utility, generate innovation because focus will not be solely on a core set of autosomal STRs, promote the development of better systems that can analyze more challenging samples, and enable sharing of data across laboratories worldwide. The primary goal of this project was to develop the capability of typing reference samples for a large battery of markers: 84 autosomal, Y-chromosome, and X-chromosome short tandem repeats (STRs), Amelogenin, and 275 human identity single nucleotide polymorphisms (SNPs), in a single multiplex analysis. To that end, a bioinformatic software package, STRait Razor, was developed to detect STR alleles in raw MPS data. A proof-of-concept study was performed to evaluate the efficacy of using MPS to type forensically relevant markers, using a PCR multiplex-based SNP assay. The proposed comprehensive capture-based MPS panel then was designed and extensively tested. Finally, the benefits of the additional genetic data afforded by MPS, as opposed to traditional methods, were illustrated through the characterization of intra-repeat nucleotide variation within Y-chromosome STR alleles. The results of this dissertation research indicate that MPS is capable of providing robust genetic data from a wide variety of forensically-relevant STR and SNP loci in a single analysis. To date, the comprehensive MPS panel developed during the course of these studies is the most potentially informative assay for reference sample testing for human identification.Item Developmental Validation of a MPS Workflow with a PCR-Based Short Amplicon Whole Mitochondrial Genome Panel(MDPI, 2020-11-13) Cihlar, Jennifer Churchill; Amory, Christina; Lagace, Robert; Roth, Chantal; Parson, Walther; Budowle, BruceFor the adoption of massively parallel sequencing (MPS) systems by forensic laboratories, validation studies on specific workflows are needed to support the feasibility of implementation and the reliability of the data they produce. As such, the whole mitochondrial genome sequencing methodology-Precision ID mtDNA Whole Genome Panel, Ion Chef, Ion S5, and Converge-has been subjected to a variety of developmental validation studies. These validation studies were completed in accordance with the Scientific Working Group on DNA Analysis Methods (SWGDAM) validation guidelines and assessed reproducibility, repeatability, accuracy, sensitivity, specificity to human DNA, and ability to analyze challenging (e.g., mixed, degraded, or low quantity) samples. Intra- and inter-run replicates produced an average maximum pairwise difference in variant frequency of 1.2%. Concordance with data generated with traditional Sanger sequencing and an orthogonal MPS platform methodology was used to assess accuracy, and generation of complete and concordant haplotypes at DNA input levels as low as 37.5 pg of nuclear DNA or 187.5 mitochondrial genome copies illustrated the sensitivity of the system. Overall, data presented herein demonstrate that highly accurate and reproducible results were generated for a variety of sample qualities and quantities, supporting the reliability of this specific whole genome mitochondrial DNA MPS system for analysis of forensic biological evidence.Item Evaluation and Validation of Tecan Genios Microplate Reader for Quantification and Normalization of Family Reference DNA Samples(2007-08-01) Fuqua, Lauren; John Planz; Arthur Eisenberg; Joseph WarrenIn 2001, the Texas State legislation established the Texas Missing Persons DNA Database (TMPDD) at the University of North Texas System Center for Human Identification Laboratory. Texas was the first state to participate in the missing persons section of the federal (FBI) database titles Combined DNA Index System or CODIS. Two indices of CODIS include the Unidentified Human Remains index and the Relatives of Missing Person index. Medical specimens, such as bone marrow or blood, or personal items used only by the missing person, such as a toothbrush or hairbrush, are ideal for identifying human remains through comparison of DNA profiles; although, DNA samples can be taken from family members to help locate missing persons or identify remains. DNA profiles from family reference samples, such as blood or buccal swabs from a close relative, are analyzed and uploaded into CODIS to allow federal, state, and local crime laboratories to exchange and compare profiles to missing persons electronically. At the University of North Texas Health Science Center, family reference samples, missing person reference samples, and unidentified human remains are analyzed to obtain DNA profiles for comparison. This research project involves a method that is proposed to improve the efficiency of DNA analysis for family reference samples. At the UNT System Center for Human Identification laboratory, the family reference samples are extracted in batches of 86 using the Tecan Freedom EVO® 100 extraction robot with the DNA IQ™ extraction kit from Promega Corporation. The DNA IQ™ extraction process is used in conjunction with the EVO® 100 robot in order to obtain a consistent amount of total extracted DNA; although, substantial variation has been detected in the output DNA quantity delivered. A considerable percentage (~20%) of samples exceed the optimal input template DNA amount required for successful amplification using the Applied Biosystems AmpFʅSTR® kits. A method of normalizing these samples was needed to bring the standard input DNA range within the optimal analytical range of the Applied Biosystems 3130 Genetic Analyzers and GeneMapper™ ID software. The ultimate objective of this internship practicum was to improve the efficiency of DNA analysis for family reference samples by using the Tecan GENios microplate reader in conjunction with an OliGreen® assay to estimate DNA quantity with the aim of using the quantification values to normalize family reference samples into an ideal input range for genetic analysis.Item Evaluation of a Novel Dual Biometric Device Used to Obtain DNA from Fingerprints(2008-06-01) Mann, Michael L.; Arthur Eisenberg; John Planz; Joseph WarrenSummary: MICROFIELD COMPANY S.A. is currently developing a non intrusive method of obtaining a reference DNA sample known as Lift & Rub (Figure 1). The Lift & Rub is a self-adhesive security stamp designed to collect a single fingerprint from a known individual that can be used for DNA analyses. Lift & Rub is composed of an adhesive material with a protective film. The Lift & Rub is composed of an adhesive material with a protective film. The Lift & Rub is used in conjunction with an abrasive strip and a product named Dry-Ink, a graphite laminate. Together these items allow for an alternative to the traditional fingerprint collection technique and improve on it by allowing for DNA analysis. The objective of this research is test and maximize the performance of Lift & Rub. Microfield’s Lift & Rub is designed to collect a single fingerprint from a known individual to be used for DNA analyses. The Lift & Rub is intended to provide a full genetic profile of a known individual. This project aims to: 1) establish a standard collection protocol by evaluating empirical data to determine the average DNA yields using various collection techniques; 2) evaluate the reproducibility of DNA profiles obtained; and 3) gauge the overall success rate of obtaining a complete profile.Item Evaluation of Applied Biosystems' Real-Time Human Quantification Assays(2003-05-01) Hybki, Dixie Lee Peters; John Planz; Arthur Eisenberg; Joseph WarrenTo aid the forensic community with its quantification issues, Applied Biosystems is currently developing human specific and human male specific quantification assays using Real-Time PCR (RT-PCR) and TaqMan probes. The human specific assay amplifies an autosomal specific gene, located on chromosome five, while the human male specific assay amplifies a region on the Y chromosome. The purpose of this project was to evaluate the assays with forensic samples to determine if the use of these kits would be appropriate to the forensic community. These kits are not commercially available at the time of this writing. Therefore, several details have been omitted to protect the patent and legal issues that are still pending. It is expected that these assays will surpass the sensitivity and specificity of current methods. This will not only meet, but also exceed the standard set forth by the DAB. By providing additional information such as human male DNA quantification and PCR inhibitor detection, these kits can provide what the forensic community has been lacking. The human male DNA detection and quantification is valuable in providing proof that male DNA was present in an intimate sample from a sexual assault case. This would be especially important in a case in which the offender was a vasectomized male, and for resolving mixtures of the victim and offender’s genetic profiles. The detection of PCR inhibitors for the elimination of futile genetic analysis is a novel component that would provide additional advantages. These kits will offer means for proper quantification to allow for minimal space waste, and allow for successful multiplex PCR within its optimal range. Today, STR analysis will proceed, and is often successful, even if no quantification results are obtained with current methods. The legal system questions this approach. The ability of autosomal specific and Y-chromosome specific RT-PCR quantification assays to assess low level DNA would provide the justification for subsequent analysis that would quiet the legal system’s arguments concerning human quantification.Item Evaluation of Genomiphi Whole Genome Amplification Kit for Use in Low Copy Number Forensic Cases(2004-12-01) Halsell, Lloyd F.; John Planz; Joseph Warren; Arthur EisenbergAmersham Bioscience produces the only available WGA kit, GenomiPhi DNA Amplification kit. It is a multiple displacement amplification reaction. The kit contains all reagents needed to perform WGA. Optimal amount of DNA input into the reaction is 1 ng or greater to yield 3 μg product. This amount is the optimal amount currently needed by PCR systems; however STR amplification requires the 1 ng in 10 μL of sample extract. GenomiPhi requires 1 μL of sample extract, ten times the concentrations of STR systems. The goal of this project was to evaluate the possible uses of the GenomiPhi DNA Amplification kit for use in the forensic community. The ability to amplify the entire genome without bias would benefit low copy number samples where there is little DNA to start with. One objective of the study was to determine the lower limit of input DNA into the GenomiPhi reaction. Input DNA varied from 10 ng to 7 pg. Secondly, input DNA was degraded to determine how the GenomiPhi kit will be affected by the input of less than pristine DNA. All samples were quantitated by PicoGreen assay, STR amplified with Profiler Plus and analyzed on ABI’s 310 Genetic Analyzer. Samples were analyzed before and after WGA to determine under which circumstance better results were seen.Item Evaluation of Kinship Indices for the Identification of Missing Persons(2006-07-01) Hamilton, Kristi Payne; John Planz; Arthur Eisenberg; Joseph WarrenWhen both parents are able to provide reference DNA samples, the likelihood ratio, or strength of a match, between the parents and their child will be very high for a true match. However, what happens when only one parent is available, or neither parent is available? How effective are other relatives’ DNA profiles at aiding in the identification of an unknown sample? What sort of threshold, if any, should be in place to determine whether an unknown is excluded from being the relative of the reference donor? This study aims to approach an answer these questions by analyzing a database consisted of anonymous samples from the paternity testing division of the University of North Texas Health Science Center DNA Identity Laboratory. The concentration of the study is on whether kinship indices are reliable and consistent in being able to provide information regarding a sibling relationship. Evaluation of the kinship indices of parents and siblings of different families, both within the family and outside of the family, will aid in the determination of whether or not a threshold exists, and what that threshold may be. This information will be invaluable to future cases involving unidentified remains when direct reference samples or parent reference samples are not available.Item Evaluation of the SlicPrep 96 Device for Use in Extraction of Forensic Samples on the Biomek 2000 Laboratory Automation Workstation(2005-07-01) Plopper, Farah Jo Homsi; Joseph Warren; Arthur Eisenberg; John PlanzThe purpose of this study was to evaluate the Slicprep ™ 96 Device for extraction of forensic samples on the BioMek® 2000 robot to determine if it can further automate and increase the efficiency of the extraction process as well as generate optimal DNA yields with no contamination. This validation study was not as comprehensive as PBSO's validation of the BioMek® 2000, because the platform and reagents used were the same. The differences include the use of the Slicprep™ 96 Device during extraction and the slight modifications to protocol that were made to accommodate this device.Item Evaluation of Unlabeled Primers for Sex Determination of Animal and Wildlife Samples(2006-07-01) Price, Glynis Nicola; John Planz; Arthur Eisenberg; Joseph WarrenSpecies identification is not only important in determining the origins of remains found in human forensic cases, but is also important in the growing field of nonhuman forensics. Animal forensics is an emerging discipline in the non-human forensics field. Animal forensics focuses on domestic animals, or animals that live in close contact with humans. These animals include dogs, cats, cattle, pigs, horses, sheep as well as others. Objective 1: Sensitivity - Forensic samples are often low copy number so there may be little viable or non-degraded DNA to work with. The PCR reaction needs to be optimized to determine how little DNA you can start with and still obtain accurate results. The given protocol from DNA Solutions, Inc. (Appendix A) [ 17] suggests 20ng of input DNA. In practice, this level is rarely found in forensic cases, so this assay will begin at 5ng of 9 input DNA. The dilution series will be 5ng, 2ng, 1 ng, 500pg, 250pg, 125pg, 62.5pg, 31.25pg and 15.63pg. Objective 2:PCR cycle number- As a part of sensitivity, PCR cycle number is an important part of optimizing the reaction. Since agarose gels are being run to visualize results, increased cycle number can result in increased specificity. Cycle numbers being evaluated are 26 cycles [ 17], 28 cycles, 30 cycles, 32 cycles and 34 cycles. Objective 3: Species Specificity - It must be determined if these universal primers do, in fact, bind to all species that possess the genes of interest. Samples from across the different animal classes will be evaluated to determine the specificity of the primers. The primers have already been tested on members of the deer family, with success, so a male deer sample has been sent to be used as a positive control as it shows both genes. Species of interest are mammals, birds and fish as there are many of each that are endangered and identifying the sex of the animal is an important step to identifying the individual animal.Item Evaluation of Y-STR Data Using a Duplex Gender Real-Time PCR Assay on an ABI Prism 7000 SDS Followed by Amplification with Applied Biosystems AmpFLSTR Yfiler PCR Amplification Kit(2007-08-01) Miller, Jennifer J.; John Planz; Arthur Eisenberg; Joseph WarrenQuantification is the process of determining the concentration of DNA in a sample and plays an extremely important role in the processes of amplification and STR typing. A method of quantification is mandated for a laboratory conducting forensic DNA analysis by National Standard 9.3 (1). Furthermore, anytime a forensic laboratory chooses to implement a new or novel methodology for any step in DNA analysis, a laboratory must conduct an internal validation to ensure the quality of method and any results generated on the equipment used within that laboratory are reliable, reproducible, and accurate before the method is utilized for casework analysis (1). Prior to an internal validation, the method or technology must undergo a developmental validation by the developer or manufacturer to determine conditions or limitations of the method or technology on DNA analysis of forensic samples (2). A study has shown that Y-STR results can be obtained even when the quantification of samples yields a value of 0.00ng/μl (4). The issue of the absolute lowest limit of detection in the quantification process versus input DNA concentrations of the unknown samples to yield any valuable Y-STR typing data has not been addressed. A duplex gender assay developed by Nicklas and Buel (3) has a reported detection limit of 0.5pg for the Alu probe of the duplex assay and quantification will be evaluated on a different qPCR platform than originally reported and followed by amplification using Applied Biosystems’ AmpFLSTR Yfiler PCR Amplification Kit to assess quantification limits. The goal of this internship project was to complete a preliminary evaluation of the sensitivity of a quantification methodology on a different qPCR platform under different detection parameters utilizing Y-chromosome DNA in correlation to Y-STR typing results and evaluate the data qualitatively.Item Internal Validation of Applied Biosystems Quantifiler Duo DNA Quantitation Kit For Use in Fornesic Casework(2008-08-01) Klein, Cindi Leann; Arthur Eisenberg; Joseph Warren; John PlanzKlein, Cindi Leann. Internal Validation of Applied Biosystems Quantifiler Duo DNA Quantification Kit for Use in Forensic Casework. Master of Science (Forensic Genetics), August 2008, 48 pages, 19 figures, 4 tables, 10 references. Applied Biosystems (Foster City, CA) has recently developed a new DNA quantification kit, Quantifiler Duo, which simultaneously quantitates the total amount of amplifiable human and male DNA present in a sample. The kit is a multiplex real-time PCR system based on the 5’ nuclease assay and Taqman probe-based technology. An internal validation was performed at the Harris County Medical Examiner’s Office using Quantifiler Duo and was comprised of six studies: sensitivity, reproducibility, cross-contamination, precision, mixture, and stability. The preliminary results show an increased sensitivity from the currently used Quantifiler Human and Quantifiler Y Human Male DNA Quantification kits. The accuracy and precision of the Quantifiler Duo kit was also comparable or superior to that of the current kits.
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