Thesis (MDip (Medical Technology))--Cape Technikon, 1993 / The use of genetic marker testing to resolve cases of disputed paternity, is well established. The number and range of systems used depends on the expertise of the laboratory, and for this reason various laboratories offer different systems. Standard testing includes tests in the following genetic marker systems: human leukocyte antigen (tissue) typing; red cell blood groups; and red cell enzyme and serum protein testing. The Provincial Laboratory for Tissue Immunology currently offers a range of 16 genetic marker systems capable of excluding >99% of falsely accused men. Following the discovery DNA polymorphisms, particularly VNTR DNA polymorphisms, and the commercial availability of VNTR DNA probes, PLTI decided to offer this service to our clients. This study was the initial phase in the establishment of a VNTR DNA typing laboratory and covered the determination of inter-and intra-gel accuracy and precision, selection of restriction enzyme/probe combination, and evaluation and comparison of the results of 100 disputed paternity cases tested using both standard and VNTR DNA typing. Of the 100 cases tested, in 33 cases, the putative father was excluded using standard testing. These exclusions were confirmed using VNTR DNA typing, and, furthermore, an additional two exclusions of paternity were shown using only VNTR DNA typing. In another two cases of disputed paternity, the exclusions obtained using standard tests required further confirmation. VNTR DNA typing convincingly excluded both falsely accused putative fathers. The VNTR DNA typing laboratory now functions as an integral part of the disputed paternity service. Due to the cost and time involved in VNTR DNA typing it is reserved at this stage for: those cases which require further confirmation of the results of standard testing; when the probability of paternity is low (<99.7%); or when a specific request is made.

Abstract not available

The purpose of this experiment was to determine if nucleic acid sequence based amplification (NASBA) is a suitable application for the differentiation of body fluids that might comprise a forensic evidence sample. NASBA is a sensitive RNA transcription based amplification system. NASBA could theorhetically be used for bodily fluid identification based upon amplification of tissue-specific mRNA transcripts present in a given forensic sample.Amplification of both Glyceraldehyde 3-phosphate dehydrogenase (GAPDH) and Matrix Metalloproteinase 1 1 (MMPmRNA transcripts were used to determine that NASBA could amplify body fluid transcripts and whether it could distinguish between menstrual and non-menstrual blood, respectively. GAPDH is a housekeeping gene that is constituently expressed and its mRNA transcripts could therefore be used to determine whether non-menstrual blood could be amplified using the NASBA procedure. MMP 11 is a menstrual cycle-specific gene associated with endometrial breakdown. Using the mRNA transcripts from MMP 11, NASBA could be utilized for menstrual blood identification. In this study, non-menstrual and menstrual blood samples were analyzed with NASBA both in the presence and absence of chemical contamination. Contaminants utilized ranged from commercial automotive wax, transmission fluid, brake fluid, artificial tears, hand soap, 10% bleach, and the luminol blood detecting reagent. Non-menstrual blood was aliquoted onto a 1 cm x 1 cm cotton cloth for contamination, while menstrual blood was provided on a 1 cm x 1 cm area of sterile menstrual pad. All samples underwent Tri reagent extraction to obtain RNA samples for NASBA amplification.With respect to NASBA amplification data, non-menstrual blood data (from extracted RNA and unextracted blood samples) revealed the highest levels of amplification as shown in relative fluorescence units (RFU). Uncontaminated menstrual blood revealed the second highest amplification data. In the presence of chemical contamination, high levels of amplification were observed when samples were contaminated with brake fluid and commercial hand soap. Moderately low amplification was observed with samples contaminated with transmission fluid, 10% bleach, and artificial tears. NASBA amplification was completely inhibited in the presence of automotive wax and luminol. Cycle threshold (CO values for each amplification result were also obtained from each reaction. Smaller Ct values correspond to a higher NASBAreaction efficiency and therefore larger amplification values. The Ct values obtained for each amplified sample correlate strongly with the amount of amplification observed from reaction. Based upon the results of this experiment, NASBA should be considered as a novel tool for forensic evidence analysis. / Department of Biology

Access to abstract permanently restricted to Ball State community only / Access to thesis permanently restricted to Ball State community only / Department of Biology

There is a transition nationwide on the analysis of forensic evidentiary stains containing biological material from traditional serology to Polymerase Chain Reaction (PCR) methodologies. The increased sensitivity of PCR, the limited number of alleles at each locus, and the necessity of producing unambiguous data for entry into the FBI's Combined DNA Index System make this study of extraction procedures of utmost importance. A "single tube" extraction procedure for blood stains collected onto FTA™ paper and a modified differential nonorganic extraction method from spermatozoa containing mixed stains were analyzed and compared. The extraction success was evaluated by amplification and typing of the amplified fragment length polymorphism, D1S80. These modifications of the nonorganic method utilized gave an improved separation of the spermatozoa-containing mixed stains.

No description available.

[Truncated abstract] The collection of buccal cells is common practise in the epidemiological and forensic science. Unlike venipuncture collection of blood; it is a safer, non-invasive method for collection of biological material. The methods by which these cells are collected from the inner cheek of an individual and stored are the key elements in preserving DNA. Typically, forensic samples require long term storage. Samples are commonly collected on cotton swabs and stored moist at low to ultra-low temperatures (less than -20oC). Although this is the method of choice in most forensic facilities, there are drawbacks. The samples are inherently contaminated with microflora within the oral cavity and the moisture allows a plethora of microorganisms to grow. As the time frame that has elapsed from collection to storage increases, there is an exponential increase in bacterial cells. Storage of containers containing swabs coated with cells at temperatures below 20oC is also costly due to requirements for large freezers which are running and monitored over 24 hours. In the pass 10 to 15 years, researchers have focussed on alternative ways to store buccal cells. The FTA card system by Whatman is one such development. The FTA card is unique in that it provides a means for the collection of buccal cells for storage at room temperature. DNA profiling from samples stored in this way for 11 years has been successfully achieved. The filter paper matrix of the FTA card binds and subsequently lyses cells. ... (2) The second component of this thesis describes a study which subjected cells on buccal swabs to various conditions of increased temperature over periods of time to establish if DNA could be amplified. The aim was to mimic exposure to the vigours of field conditions, particularly in the extreme local environments that prevail in the United Arab Emirates. a. Initially, buccal cells stored at -20oC over 360 days were used to mimic standard archiving procedures. The cells were subsequently transferred to FTA cards, amplified and profiled by using ABI AmpFLSTR Identifiler PCR Amplification Kit (Applied Biosystems, Foster City, CA). Complete STR profiles were successfully recovered from the archived swabs. In most cases 100% of alleles were recovered, suggesting that it is feasible to transfer DNA from properly archived buccal swabs to FTA cards. b. The second phase involved the storage of fresh swabs that had been artificially aged by using incubation temperatures ranging from 40oC to 100oC. Partial profiles resulted from artificially aged samples, indicating that the prevailing conditions prior to low temperature storage of the swabs plays an important role in ensuring cellular integrity and thus, DNA quality. Results from this study suggest that it is possible for biological samples stored under correct conditions to be transferred from swabs to FTA card. In combination, the two chapters presented in this study show that it is feasible to transfer achieved forensic biology samples from swabs to the FTA card system. However, it is necessary to ensure that the samples are treated in the correct manner so as to minimise contamination from external sources and to maintain the correct environmental state to maintain intact cells and usable DNA.

DNA profiling has ignited public interest and consequently their expectations for the capabilities of forensic criminal and science investigations. The prospect of characterising the genetic makeup of individuals or trace samples from a wide variety of depositional and post-mortem circumstances raises the question of how reliable the methods are given the potential for prolonged exposure to variation in environmental factors, i.e. temperature, pH, UV irradiation and humidity, that are known to induce damage to DNA. Thus, it is crucial to verify the validity of the DNA profiling for characterising the genetic makeup of post-mortem tissues. This project aimed to assess the reliability of sequence and microsatellite based genotyping of tissues (muscle, hair and bone) sampled from carcasses over a two year post-mortem period. This assessment investigated the impact of environment induced DNA degradation in the local geographic region that is typical of the circumstances that confront forensic practitioners in southern Australia and to utilise rigorous controls by studying animals whose time of death and burial was known and for which we had pre-decay tissue samples available. A ‘body farm’ with 12 pig carcasses on the northern Adelaide plains, ~60km north of Adelaide, which has a typical southern Australian Mediterranean climate, i.e. cold wet winters and hot dry summers. Pigs (Sus scrofa) were used as an experimental analogue for human subjects because of the logistical and ethical reasons. The pig carcasses were allocated among three treatments: four were left on the surface, four were buried at 1m depth, and four were buried at 2 m depth. These ‘burial’ conditions mimic a range of conditions encountered typically in forensic and archaeological studies. Cortical bone samples were taken from each pig carcass at one week, one month, three months, six months, one year and two years post-mortem and muscle and hair over the same sampling period for as long as those tissue types were present. A set of PCR primers to amplify two (short and a long) fragments from the hypervariable part of the mitochondrial control region (HVRI) that is used in forensic and evolutionary studies of humans and many other mammal species were developed. Also a panel of four pig microsatellite loci with fluorescent labels to facilitate automated multiplex genotyping. These loci matched as closely as possible the core motifs and allele lengths typical of the commercially available microsatellite marker kits used in Australian forensic science labs so that our experiments were as good a model as possible of the human forensic DNA technology. In this study it was possible to retrieve samples from muscle tissue up to 90 days, hair up to one year and bone at two years post-mortem. The analyses showed that the long and short HVRI region PCR fragments were only amplifiable up to 30 days from muscle tissue and that these fragments were amplifiable up to one year from hair. In contrast, in cortical bone both PCR fragments were amplifiable up to two years. The long fragment disappeared in muscle tissue completely after 30 days and in hair after six months. However, the long fragment was present in cortical bone even at two years. Overall, there was a general trend of loss of concentration of both the long and short fragments over time. Comparisons of the HVRI nucleotide sequences among tissues sampled from individual animals showed substitution changes in muscles as early as 30 days (3 out of 6 individuals) and hair at six months (1 out of 6 individuals). In contrast, in cortical bone substitutions first appeared at 365 days (1 out of 6 individuals). The most common substitution observed in all tissues types was the C-T transition, with A-G transversions observed in two episodes and C-A transversion observed in one episode. Analyses of microsatellite genotypes in muscle tissues showed high allele peaks on chromatograms up to day seven samples. However, by three months PCR was not successful from muscle tissue. While, bone tissue had lower allele peak heights compared to the muscle tissues, alleles were detectable up to six months. Allele drop out occurred for one animal (at 2 meters) in muscle tissue at the dinucleotide locus and for another animal (kept on surface) also in muscle tissue at a tetranucleotide locus. Stuttering was observed for a single animal at dinucleotide locus in muscle tissue (buried sample 2 meter depth). No stuttering or allele drop outs were seen in the bone tissue. Overall the four loci completely disappeared after 30 days in muscle tissue and after 180 days in bone tissue. In summary, analyses showed that post-mortem DNA degradation was present in all the three tissue types (muscle, hair and bone). The types of damage identified were DNA fragmentation, nucleotide substitutions and DNA loss, which resulted in a diminished frequency of successful PCR for mitochondrial and nuclear markers over time and stuttering and allele drop out in microsatellite genotyping. In addition, two nucleotide substitutions were concentrated in ‘hotspots’ that correlate with sites of elevated mutation rate in vivo. Also the frequency of successful PCR of longer nuclear and mitochondrial PCR products declined markedly more quickly than for shorter products. These changes were first observed at much shorter post mortem intervals in muscle and much longer post mortem intervals in hair and bone tissue. When considering the carcass deposition treatments, tissues that were retrieved from buried carcases showed higher levels of DNA degradation compared to tissues retrieved from carcases left on the surface. Overall, muscle tissue is a good source for DNA analysis in immediate post mortem samples, whereas hair and bone tissue are good source for DNA analysis from older samples. When comparing the microsatellite genotyping and mtDNA analyses, mtDNA is a reliable source for DNA analysis from tissue recovered from bodies that had decayed for longer post-mortem durations such as months to years, whereas microsatellite genotyping gives reliable results for tissue from shorter post mortem intervals (hours to few days). Therefore it is recommended that when analysing mtDNA sequences, cloning and sequencing PCR products can help to identify the base pair substitutions especially for tissue retrieved from longer post mortem intervals. In addition, increasing the template DNA concentrations and "neutralising" co-extracted DNA inhibitors should be considered when dealing with tissue from longer post mortem intervals. Finally, the more stringent protocols used in ancient DNA studies should be considered when dealing with tissue with much longer post mortem intervals in forensic settings. / Thesis (Ph.D.) -- University of Adelaide, School of Medical Sciences, 2009

Indiana University-Purdue University Indianapolis (IUPUI) / Short tandem repeat (STR) analysis is currently the most common method for processing biological forensic evidence. STRs are highly polymorphic and allow for a strong statistical power of discrimination when comparing deoxyribonucleic acid (DNA) samples. Since sample testing and court proceedings occur months, if not years apart, samples must be stored appropriately in the event additional testing is needed. There are generally accepted methods to store DNA extracts long-term; however, one universally recognized method does not exist. The goal of this project was to examine various methods of storage and make recommendations for a universal storage method that maintained DNA integrity over time. Four variables were evaluated: storage buffer, storage temperature, initial storage concentration and the effects of repeated freeze-thaw cycles. DNA quantity was assessed using real-time polymerase chain reaction and DNA quality was evaluated using STR genotyping. Overall, the Tris-EDTA (TE) buffer outperformed nuclease free water as a long-term storage buffer for DNA extracts. Stock tubes stabilized concentration better than single use aliquots when eluted with TE while tube type was not significant when water was the buffer. For samples stored in TE, temperature had no effect on DNA integrity over time, but samples stored in water were largely affected at room temperature. Additionally, the greater the initial DNA concentration, the less likely it was to degrade in water. As a result of this research, DNA extracts from forensic samples should be stored long-term in TE buffer with a minimum concentration of 0.1 ng/μL. When water is the buffer, frozen storage is recommended.

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.