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PubMed1999

The utility of short tandem repeat loci beyond human identification: implications for development of new DNA typing systems.

Since the first characterization of the population genetic properties of repeat polymorphisms, the number of short tandem repeat (STR) loci validated for forensic use has now grown to at least 13. Worldwide variations of allele frequencies at these loci have been studied, showing that variations of interpopulation diversity at these loci do not compromise the power of identification of individuals. However, data collected for validation of these loci for forensic use has utility beyond human identification; the origin and past migration history of modern humans can be reconstructed from worldwide variations at these loci. Furthermore, complex forensic cases previously unresolvable can now be investigated with the help of the validated STR loci. Here, we provide the absolute power of the validated set of 13 STR loci for addressing these issues using multilocus genotype data on 1,401 individuals belonging to seven populations (US European-American, US African-American, Jamaican, Italian, Swiss, Chinese and Apache Native-American). Genomic research is discovering new classes of polymorphic loci (such as the single nucleotide polymorphisms, SNPs) and lineage markers (such as the mitochondrial DNA and Y-chromosome markers); our aim, therefore, was to determine how many SNP loci are needed to match the power of this set of 13 STR loci. We conclude that the current set of STR loci is adequate for addressing most problems of human identification (including interpretations of DNA mixtures). However, if suitable number of SNPs are used that would match the power of the STR loci, they alone cannot resolve more complex cases unless they are supplemented by the validated STR loci.

Chromosome Mapping↗
PubMed2005

A PCR multiplex and database for forensic DNA identification of dogs.

Animal-derived trace evidence is a common finding at crime scenes and may provide an important link between victim(s) and suspect(s). A database of 558 dogs of pure and mixed breeds is described and analyzed with two PCR multiplexes of 17 microsatellites. Summary statistics (number of alleles, expected and observed heterozygosity and power of exclusion) are compared between breeds. Marked population substructure in dog breeds indicates significant inbreeding, and the use of a conservative theta value is recommended in likelihood calculations for determining the significance of a DNA match. Evidence is presented that the informativeness of the canine microsatellites, despite inbreeding, is comparable to the human CODIS loci. Two cases utilizing canine DNA typing, State of Washington v. Kenneth Leuluaialii and George Tuilefano and Crown v. Daniel McGowan, illustrate the potential of canine microsatellite markers for forensic investigations.

Animals↗
PubMed2005

[Genetic polymorphism of D1S1612 and D18S535 in Chinese Han population of Beijing].

To investigate the genetic polymorphism of D1S1612 and D18S535 in Han population of Beijing. Amp-FLP method was used. 9 alleles, 25 genotypes were observed for D1S1612 locus; and 9 alleles and 27 genotypes for D18S535 locus. All allele frequencies, heterozygosity (H), discrimination power (Dp), exclusion of paternity probability (PE) and polymorphism information content (PIC) were calculated. The allele distributions of the two loci were conformed to Hardy-Weinberg equilibrium (P>0.01). According to the results obtained in this study, it is suggested that both D1S1612 and D18S535 are useful genetic markers for individual identification and paternity testing in forensic science practice as well for genetic study.

Alleles↗
PubMed1997

Genetic individualization of domestic cats using feline STR loci for forensic applications.

A group of ten short tandem repeat (STR) loci suitable for PCR typing from DNA of domestic cats is evaluated for genetic individualization using blinded samples of eight putative feline blood specimens. The ten loci were also typed in a 70 member cat pedigree to demonstrate Mendelian inheritance and independent assortment. A "match window" or measurement precision estimate was empirically established by determining the maximum gel migration difference among alleles identical by descent in different individuals of the pedigree. Hardy-Weinberg equilibrium and abundant heterozygosity was observed for each locus in cat population samples from Canada and the USA. The probabilities of two unrelated individuals matching by chance (Pm) at all ten loci was estimated as 1.35 x 10(-10). We present a conservative approach to compute, for forensic consideration, the mathematical likelihood of a chance genotypic match between DNA evidence from a crime scene and the suspect composite STR genotypes for species or populations when genotype frequency information is not available.

Animals↗
PubMed1989

A genetic electrophoretic variant of high-sulfur hair proteins for forensic hair comparisons. II. Practical application of electrophoretic analysis of hair protein to forensic hair comparisons.

The influence of weathering and cosmetic treatment on the analysis of human hair-carboxymethylated protein has been studied by a 15% polyacrylamide gel electrophoresis. Usual cosmetic treatment, i.e., permanent waving, dyeing, and bleaching, and weathering, i.e., hair samples that had been buried for up to 2 years, did not evidence any significant change in their electrophoretic patterns, though weathering for 2.5 years or longer made it difficult to determine the electrophoretic patterns. Capillary gel disc electrophoresis of a single, 5 cm, hair strand, which previously had been subjected to ABO blood group determination by an absorption-elution test, was sufficient to provide a multiple protein pattern analysis. Successful use of this analysis in a forensic case is described.

Electrophoresis, Polyacrylamide Gel↗
PubMed2000

[Polymorphisms of four STRs and their associations with IDDM in Chinese Han population].

OBJECTIVE: To obtain the polymorphic data of short tandem repeat(STR) loci of D15S657, D11S1369, D6S2420 and D6S503 in Chinese Han population and to study the association of these four STR loci with insulin-dependent diabetes mellitus(IDDM). METHODS: The polymorphisms of the four STRs were studied by polymerase chain reaction-polyacrylamide gel electrophoresis(PCR-PAGE) followed by direct sequencing of PCR products in 105 normal Chinese Hans and 48 patients with IDDM. RESULTS: Seven alleles at D15S657 locus, 5 alleles at D11S1369 locus, 7 alleles at D6S2420 locus and 4 alleles at D6S503 locus were found. No deviation from Hardy-Weinberg equilibrium was observed. The heterozygosities of these loci were 0. 7524, 0.6000, 0.6286, 0.6571 and the polymorphic information contents(PIC) 0.7616, 0.4430, 0.5345 and 0.5932, respectively. The allele frequencies of allele A(5) at D15S657 locus, allele A(5) at D11S1369 locus and allele A(4) at D6S2420 locus were increased significantly in patients with IDDM, compared to those in the control group. CONCLUSION: The four STRs, used as genetic markers, were suitable for case-control study, forensic medicine identification and population genetic study. There is an association between the polymorphisms of D15S657, D11S1369, D6S2420 and IDDM.

Adult↗
PubMed1992

Biology and applications of human minisatellite loci.

Highly repetitive minisatellites' include the most variable human loci described to date. They have proved invaluable in a wide variety of genetic analyses, and despite some controversies surrounding their practical implementation, have been extensively adopted in civil and forensic casework. Molecular analysis of internal allelic structure has provided detailed insights into the repeat-unit turnover mechanisms operating in germline mutations, which are ultimately responsible for the extreme variability seen at these loci.

Chromosome Mapping↗
PubMed1997

An improved high resolution single method for orosomucoid ORM1 and ORM2 phenotyping.

An improved high resolution single method for orosomucoid ORM1 and ORM2 phenotyping using isoelectric focusing (IEF) in wide-scales ultrathin layer polyacrylamide gels of pH range 4.2 to 4.9 is presented. The method is reliable, simple, and provides an alternative for the three currently required ones for typing this genetic system.

Electrophoresis, Polyacrylamide Gel↗
PubMed2006

[PCR-multiplex system for analysis of Y-chromosomal microsatellite polymorphisms DYS449, DYS456, DYS458, and DYS464].

DNA profiling--inclusive sex determination-- with microsatellite markers is currently a commonly used genetic method of studying humans. An efficient technique of producing the genetic data is amplification of multiple microsatellites in a single PCR reaction. Here we introduce a novel PCR-multiplex system for analysis of four polymorphic Y-STRs. Specifically, these are DYS449, DYS456, DYS458, and DYS464. These loci were chosen because of their reported high diversity in Euroamerican population (10), as well as their absence in the commercial analytical kits at the time of beginning of this study. Our objective was to design this PCR-multiplex for use of fragmentation analysis by electrophoresing samples on a capillary semi-automated genetic analyzer applying only one fluorescent dye. The PCR system we propose, may be notably used in fields such as forensic and human population genetics.

Chromosomes, Human, Y↗
PubMed1991

[DNA analyses in forensic investigations].

Variable number of tandem repeat (VNTR) polymorphisms are used as genetic markers in paternity testing and forensic investigation. The blot patterns obtained with single locus probes are easily interpreted, and the fragment sizes can be calculated for further statistical evaluation. Fragments cleaved with Hinf I and analysed with the probe YNH 24 were found to vary in estimated size within +/- 1.5 per cent of the number of base pairs. In paternity testing, a window of +2.5 per cent will yield a risk of false exclusion of less than 1 in 10(6), with an estimated exclusion rate of about 90 per cent. In paternity testing, electrophoresis of mixed DNA samples from the child and the suspected father yields significant information irrespective of exclusion. The mean calculated paternity index for non-excluded men obtained with the YNH 24 probe was 8.4 (range, 2.6-19.2).

Blood Grouping and Crossmatching↗
PubMed2005

A new Web site compiling forensic chromosome X research is now online.

We would like to announce the opening of a new Web site ( http://www.chrx-str.org ), which contains a database surveying current research on chromosome X markers used for forensic purposes, evolutionary anthropology and other genetic research. Currently, we summarise short tandem repeat data with regard to the physical and genetic localisation, repeat structure, allele nomenclature, mutation rates and population genetics. In the future, we may include diallelic markers. The results contained in this database come from published journal articles. The authors of published articles are invited to complement their own papers by submitting data obtained from follow-up studies here. Furthermore, population data which are not able to find space in journals may be published at this Web site. The growing field of ChrX haplotyping is producing an extensive amount of data, which requires a place that can complement journal publications.

Chromosomes, Human, X↗