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Autosomal STR variation in five Austronesian populations.

Human population characteristics at the genetic level are integral to both forensic biology and population genetics. This study evaluates biparental microsatellite markers in five Austronesian-speaking groups to characterize their intra- and interpopulation differences. Genetic diversity was analyzed using 15 short tandem repeat (STR) loci from 338 unrelated individuals from 5 Pacific islands populations, including the aboriginal Ami and Atayal groups from Taiwan, Bali and Java in Indonesia, and the Polynesian islands of Samoa. Allele frequencies from the STR profiles were determined and compared to other geographically targeted worldwide populations procured from recent literature. Hierarchical AMOVA analysis revealed a large number of loci that exhibit significant correspondence to linguistic partitioning among groups of populations. A pronounced divide exists between Samoa and the East (Formosa) and Southeast Asian (Bali and Java) islands. This is clearly illustrated in the topology of the neighbor-joining tree. Phylogenetic analyses also indicate clear distinctions between the Ami and Atayal and between Java and Bali, which belie the respective geographic proximities of the populations in each set. This differentiation is supported by the higher interpopulation variance components of the Austronesian populations compared to other Asian non-Austronesian groups. Our phylogenetic data indicate that, despite their linguistic commonalities, these five groups are genetically distinct. This degree of genetic differentiation justifies the creation of population-specific databases for human identification.

Asian People↗

DNA mixtures: biostatistics for mixed stains with haplotypic genetic markers.

The conventional theory for interpreting forensic DNA evidence developed for the autosomal genetic markers is not applicable in the case of haplotypic markers, specifically for Y-STR based data. The reason is, that in contrast to the case of autosomal markers, single alleles found in the mixed stain cannot be assigned to unknown stain contributors independently of each other, while the assignable entities are sets of linked alleles which should be treated as non-separable units. It is shown that the conventional theory cannot be extended to this situation. A novel theory which accounts for the features of haplotypic markers has been developed within the general framework of the hypotheses testing approach. This theory opens the way for the use of haplotypic markers in the analysis of mixed stains with the arbitrary numbers of unknown contributors and linked loci. A numerical example demonstrates the application of the theory.

Alleles↗

[Practical use of the molecular-genetic technologies in solving the tasks of forensic medical identification of remains in emergencies with huge human death toll].

Previously, we have developed different variants, for the expert use, of information technologies, i.e. of computer automated analytical systems, to ensure an effective analysis of huge bulwarks of molecular-genetic expert findings. The results obtained in the above research significantly advanced the possibilities of expert evaluation related with personality identification under the conditions of a big death toll; they also cleaned the ground for the introduction of such methodological approaches in the practice of investigations of emergency accidents involving huge death tolls. Described within the present case study is a practical experience of forensic medical identification of unrecognized remains in air crashes with huge human death tolls implemented through computer-assisted complex molecular-genetic tests on the basis of indirect DNA identification involving the establishment of blood relationship.

Accidents, Aviation↗

Recommendations for animal DNA forensic and identity testing.

Genetic analysis in animals has been used for many applications, such as kinship analysis, for determining the sire of an offspring when a female has been exposed to multiple males, determining parentage when an animal switches offspring with another dam, extended lineage reconstruction, estimating inbreeding, identification in breed registries, and speciation. It now also is being used increasingly to characterize animal materials in forensic cases. As such, it is important to operate under a set of minimum guidelines that assures that all service providers have a template to follow for quality practices. None have been delineated for animal genetic identity testing. Based on the model for human DNA forensic analyses, a basic discussion of the issues and guidelines is provided for animal testing to include analytical practices, data evaluation, nomenclature, allele designation, statistics, validation, proficiency testing, lineage markers, casework files, and reporting. These should provide a basis for professional societies and/or working groups to establish more formalized recommendations.

Animals↗

[Study on application of Tf subtyping in forensic medicine].

Tf is an important genetic marker for both parentage testing and personal identification in forensic medicine. It is valuable in anthropology, genetics and clinical medicine. We examined the Tf subtypes in the human serum and dried bloodstain using the ULPAGIF method. Tf subtyping was performed in four disputed parentage cases. One of the alleged fathers was excluded. Tf subtypes were successfully demonstrated from dried bloodstains kept at 4 degrees C for up to four weeks. In bloodstains kept at room temperature and 37 degrees C, the 100% of Tf subtyping was no longer possible after two weeks (or one day). It was suggested that the bloodstains should be examined no longer than seven weeks if the bloodstains were kept at room temperature; or otherwise they should be stored below 4 degrees C as soon as they are collected in forensic practice.

Blood Stains↗

Reference database of hypervariable genetic markers of Argentina: application for molecular anthropology and forensic casework.

The population of Argentina is mostly composed of people of European ancestry. Aboriginal communities are at present very reduced in number and restricted to small geographically isolated patches. Three aboriginal communities, the Mapuche, Tehuelche and Wichi, were selected for short tandem repeat (STR) investigation. The metropolitan population of the city of Buenos Aires was analyzed, with both micro- and minisatellites. The minisatellite loci D1S7, D2S44, D4S139, D5S110, D8S358, D10S28, and D17S26 were typed on HaeIII-digested DNA obtained from unrelated individuals. D1S80 was typed by polymerase chain reaction (PCR). The autosomal STRs THO1, FABP, D6S366, CSF1PO, TPOX, F13A1, FES/FPS, vWA, MBPA/B, D16S539, D7S820, D13S317, and RENA4 and the sex chromosome STRs HPRTB, DYS385, DYS3891, DYS38911, DYS19, DYS390, DYS391, DYS392, DYS393 and YCAII were also investigated. As a by-product of our investigations, a reference database was created that is routinely used in forensic casework and paternity testing. STR allele frequency distributions are characterized by significant differences within and also between different populations. In contrast, the minisatellite bin distribution of the metropolitan population is not significantly different from other Caucasian populations.

Alleles↗

Sudden cardiac death in the young: a clinical genetic approach.

The sudden death of a young person is a devastating event for both the family and community. Over the last decade, significant advances have been made in understanding both the clinical and genetic basis of sudden cardiac death in the young. Many of the causes of sudden death in the young are due to genetic heart disorders, which can lead to both structural (e.g. hypertrophic cardiomyopathy) and arrhythmogenic (e.g. familial long QT syndrome) abnormalities. Most commonly, sudden cardiac death in the young can be the first presentation of an underlying heart problem, leaving the family at a loss as to why an otherwise healthy young person has died. Not only is this a tragic event for those involved, but it also presents a medical challenge to the clinician involved in the management of the surviving family members. Evaluation of families requires a multidisciplinary approach, which should include cardiologists, a clinical geneticist, a genetic counsellor and the forensic pathologist directly involved in the sudden death case. This multifaceted cardiac genetic service is crucial in the evaluation and management of the clinical, genetic, psychological and social complexities observed in families in which there has been a young sudden cardiac death.

Adolescent↗

Summary of validation studies from twenty-six forensic laboratories in the United States and Canada on the use of the AmpliType PM PCR amplification and typing kit.

A cooperative study was undertaken to collect and summarize the results of validation studies from forensic laboratories in the United States and Canada on the use of the AmpliType PM PCR amplification and typing kit for genetic typing of forensic biological evidence. This report compiles data from 26 laboratories on: 1) reproducibility studies on DNA extracted from various samples, 2) genetic typing of DNA extracted from a variety of biological samples on various substrates, 3) the effects of exogenous chemicals, materials, and environmental factors on test results, 4) sensitivity studies to determine the least detectable amount of extracted genomic DNA that can be reliably typed, 5) analysis of mixtures containing two sources of genomic DNA, 6) cross-hybridization with DNA extracted from various nonhuman species, and 7) evaluation of assay performance on parallel studies with other genetic typing systems on proficiency test panels, mock cases, and adjudicated/nonprobative casework. Equivalent results were obtained by each laboratory that supplied data, demonstrating the reliability and consistency of the test. Overall, it can be concluded from this study that the AmpliType PM PCR amplification and typing kit meets the guidelines of the Technical Working Group on DNA Analysis Methods (TWGDAM) and there is general scientific acceptability of this kit for forensic DNA testing.

Canada↗

Molecular characterisation of the nucleic acids recovered from aged forensic samples.

The molecular composition of the genetic substrate recovered from seven aged forensic samples has been extensively investigated. A simple enzymatic test based on DNAseI incubation of the extracts showed that the UV-fluorescent material from the forensic specimens is composed of nucleic acids, with the DNA fraction representing at least 90% of the total amount. Since spectrophotometric determinations of the extracts showed unreliable results due to anomalous OD(260)/OD(280) ratios, quantification of the nuclease-sensitive genetic material was performed by a slightly modified agarose plate method. The first quantitative data on exogenous contamination in aged forensic samples are provided by slot-blot hybridisation of the extracts to human, bacterial and fungal probes. Only limited amounts of human and contaminant DNA were detected in the samples. The molecular integrity of the primary structure of these aged DNA samples was analysed by reversed-phase HPLC/MS. The data show a good correlation between the degree of chemical damage and the ability to hybridise to molecular probes. The ability to achieve specific genetic profiles was assessed by multiplex PCR amplification of STR loci. Our data show that accurate determination of the molecular composition of the DNA recovered from forensic samples can be extremely useful for a reliable evaluation of the PCR typing results.

Age Factors↗

Behavior of genetic markers in recipients after bone marrow transplantation and problems in forensic medicine.

The authors report studies on four pairs of donors and recipients in bone marrow transplantation (BMT). A broad range of gene markers at 41 gene loci, including 11 red blood cell markers, 5 human lymphocyte antigen (HLA) types, 12 serum protein markers, 5 red cell enzyme markers, and 8 salivary markers were evaluated before and after BMT over 2 months. As a result, 9 out of 41 gene loci of genetic markers in recipients were transformed into the donor type. BMT between family members may lead to transformation of gene markers, but within a pattern compatible with family inheritance patterns, and no genetic paradox will be found in later surveys of familial genetic relationships. However, in a personal identification system in forensic medicine using genetic markers as an index, the appearance of a phenotype incompatible with a blood relationship is possible after BMT with a non-blood-relative donor. This result is similar to the inheritance pattern observed after artificial insemination by a donor's semen (AID), a more complete out-of-family cross.

Blood Group Antigens↗

Genetic profiling of a central Venezuelan population using 15 STR markers that may be of forensic importance.

The AmpFlSTR Identifiler kit has recently been accepted for use in DNA databasing of forensic samples in the FBI's National DNA Index System. In the present study, we used this kit to analyze the allele distribution of 15 short tandem repeat markers (STR) in individuals living in Caracas city, Venezuela. The allele frequencies of two of these STR, D2S1338 and D19S433, have not previously been reported for this or any other Latin American population. The results indicate that for the population here studied, the 15 STR tested are useful markers for paternity testing and forensic casework.

Alleles↗

Use of X-linked markers for forensic purposes.

In forensic science, X-chromosomal short tandem repeats (ChrX STRs) bear the potential to efficiently complement the analysis of other genetic markers (autosomal, Y-chromosomal or mitochondrial). We review the population genetic properties and forensic utility of selected ChrX markers, and discuss the problems and limitations arising with their practical use. Formulae required to assess the evidential power of individual markers in different contexts are summarised and applied to ChrX STRs of interest. Since linkage and linkage disequilibrium between markers affect the inferential interpretation of genotype data, practically relevant information regarding the co-localisation and haplotypic association of ChrX STRs is provided. Finally, two examples of complex kinship testing are presented which serve to highlight the particular importance of ChrX STRs for solving deficiency cases and cases involving blood relatives.

Chromosome Mapping↗

Hypervariable polymorphic VNTR loci for parentage testing and individual identification.

Three kinds of variable number of tandem repeat DNA probes (VNTR: pYNZ22, pYNH24, and pYNZ2) showing hypervariable polymorphisms were studied. Allelic frequencies and their confidence intervals among Japanese individuals were obtained. Co-dominant segregation of the polymorphism was confirmed in family studies. Two a priori probabilities were calculated for each VNTR locus: exclusion probabilities for an alleged father/mother/child trio and for an alleged parent/child duo, and probabilities of matching of genotyped two unrelated individuals or two siblings. Availability as well as highly discriminating polymorphic pattern of VNTR loci makes it potentially very useful for forensic and human genetic purposes.

Alleles↗

Matrix-assisted laser desorption/ionization for short tandem repeat loci.

Matrix-assisted laser desorption/ionization was used for the detection of four base short tandem repeats (STR) for clinical samples using a time-of-flight mass spectrometer. Since STR plays an important role in genetic disease and human identification, this work indicates that laser desorption mass spectrometry has the potential to achieve rapid DNA typing for both forensic applications and genetic disease diagnosis.

DNA↗

A case of double alleles at three Y-STR loci: forensic implications.

In a genetic study of unrelated donors from Bahia (Brazil), one sample contained a 16 Y-STR haplotype with double peaks at three loci: DYS389 II, DYS437 and DYS439. The son of the subject had the same haplotype as found in the father. This profile was compared with a similar case found in a paternity case investigation in Madrid (Spain) and a match was found for the full 16 Y-STR haplotype. Because these three loci are located within the AZFa segment, these results are in accordance with duplication of the AZFa region that includes also other Y-STRs currently used in forensic investigation, for example DYS389I and DYS438. This case attracts our attention in the forensic interpretation of Y-haplotype profiles, because multiple alleles at various loci do not indicate forcibly that the sample under analysis is a mixture.

Brazil↗

[Genetic polymorphism of 10 STR loci on chromosome 9 and its forensic application in Chinese population].

OBJECTIVE: To have a thorough knowledge of the genetic polymorphism of 10 short tandem repeats loci of chromosome 9 in Chinese population and its application in forensic science. METHODS: The 9 STR tetrameric loci and one trimeric tandem repeat locus were chosen from Genome Databank. Eighty-three EDTA-blood samples were collected from the unrelated family in Baiyin city, Gansu province. DNA was extracted by Chelex method and amplified by the polymerase chain reaction(PCR). The PCR products were analyzed by PAGE electrophoresis. RESULTS: The polymorphisms of all 10 STR loci have been obtained in Chinese Han population. The 10 STR loci follow the Mendel ns law. CONCLUSION: The data of all 10 STR loci is beneficial to understanding the population genetics of them in Chinese Han population.

Chromosomes, Human, Pair 9↗