ABSTRACT
The reference database of highly informative Y-chromosomal short tandem repeat (STR) haplotypes (YHRD), available online at http://ystr.charite.de, represents the largest collection of male-specific genetic profiles currently available for European populations. By September 2000, YHRD contained 4688 9-locus (so-called "minimal") haplotypes, 40% of which have been extended further to include two additional loci. Establishment of YHRD has been facilitated by the joint efforts of 31 forensic and anthropological institutions. All contributing laboratories have agreed to standardize their Y-STR haplotyping protocols and to participate in a quality assurance exercise prior to the inclusion of any data. In view of its collaborative character, and in order to put YHRD to its intended use, viz. the support of forensic caseworkers in their routine decision-making process, the database has been made publicly available via the Internet in February 2000. Online searches for complete or partial Y-STR haplotypes from evidentiary or non-probative material can be performed on a non-commercial basis, and yield observed haplotype counts as well as extrapolated population frequency estimates. In addition, the YHRD website provides information about the quality control test, genotyping protocols, haplotype formats and informativity, population genetic analysis, literature references, and a list of contact addresses of the contributing laboratories.
Subject(s)
Databases, Factual , Haplotypes , Tandem Repeat Sequences/genetics , Y Chromosome/genetics , Europe , Genetics, Population , Humans , MaleABSTRACT
A 9-locus microsatellite framework (minimal haplotype), previously developed for forensic purposes so as to facilitate stain analysis, personal identification and kinship testing, has been adopted for the establishment of a large reference database of male European Y-chromosomal haplotypes. The extent of population stratification pertaining to this database, an issue crucial for its practical forensic application, was assessed through analysis of molecular variance (AMOVA) of the 20 regional samples included. Despite the notion of some significant haplotype frequency differences, which were found to correlate with known demographic and historic features of Europeans, AMOVA generally revealed a high level of genetic homogeneity among the populations analyzed. Owing to their high diversity, however, accurate frequency estimation is difficult for Y-STR haplotypes when realistic (i.e. moderately sized) datasets are being used. As expected, strong pair-wise and higher order allelic associations were found to exist between all markers studied, implying that haplotype frequencies cannot be estimated as products of allele frequencies. A new extrapolation method was therefore developed which treats haplotype frequencies as random variables and generates estimates of the underlying distribution functions on the basis of closely related haplotypes. This approach, termed frequency 'surveying', is based upon standard population genetics theory and can in principle be applied to any combination of markers located on the Y-chromosome or in the mitochondrial genome. Application of the method to the quality assured reference Y-STR haplotype database described herein will prove very useful for the evaluation of positive trace-donor matches in forensic casework.
Subject(s)
Genetics, Population , Haplotypes , Tandem Repeat Sequences , Y Chromosome/genetics , Alleles , Databases, Factual , Europe , Forensic Medicine/methods , Genome, Human , Humans , Male , Regression AnalysisABSTRACT
A hypervariable region has been described 3' to the human apolipoprotein B (apo B) gene. Using the polymerase chain reaction amplification followed by agarose gel electrophoresis, at least 16 different alleles can be distinguished. In order to introduce this system into forensic DNA analysis detailed knowledge of the allele frequency is one of the most important prerequisites. For this reason we studied the allele distribution of 340 unrelated individuals originating predominantly from Southern Germany.
Subject(s)
Alleles , Apolipoproteins B/genetics , DNA/analysis , Gene Frequency , Polymorphism, Restriction Fragment Length , Base Sequence , DNA/chemistry , Electrophoresis, Agar Gel , Genotype , Germany , Humans , Molecular Sequence Data , Polymerase Chain Reaction , Repetitive Sequences, Nucleic AcidABSTRACT
In 39 cases of SID we studied the polymorphism of HLA-class II genes DRB and DQB and HLA-class III genes C4 (C4A and C4B, genes encoding the fourth complement component) and 21-hydroxylase (21OH-A and 21OH-B, genes encoding the enzyme 21-hydroxylase of the cortisol pathway) by DNA analysis. This study was performed in cooperation with the Institute of Legal Medicine, University of Munich. Compared to healthy controls the percentage of C4B gene deletions, C4B gene duplications (C4B "short") and 21OH-A gene deletions is increased in SIDS. The deviations are statistically not significant. The analysis of the HLA-DR alleles revealed a significant decrease of HLA-DR2 in SIDS compared to controls (p = 0.0016, pc = 0.016). The results of this study indicate a possible role of C4B/21OH-A gene defects as a risk factor in a subgroup of SID cases. This hypothesis has to be confirmed by studying further cases.
Subject(s)
Chromosome Aberrations/genetics , Genes, MHC Class II/genetics , Genetic Markers/genetics , Sudden Infant Death/etiology , Chromosome Deletion , Complement C4b/genetics , Female , Gene Frequency/genetics , Humans , Infant , MaleABSTRACT
The species of raw meat as well as heat-processed meat can be determined by DNA dot-blot hybridization-techniques. We investigated on artificially degraded DNA whether various DNA qualities could influence the validity of the experiment results. We demonstrated that degraded DNA could also react according to the species. The shorter the DNA fragments, the discreter was the reaction when high molecular weight DNA was used as a probe. This effect is not observed with degraded DNA as a probe.
Subject(s)
DNA Probes , DNA/genetics , Immunoblotting , Nucleic Acid Hybridization , Species Specificity , Animals , Cattle , Humans , Peptide Fragments/genetics , SwineABSTRACT
The species of a biological sample (blood, hairs) was determined by hybridization of its DNA with specific control DNA using either the former or the latter as probe. The labelling of the probes occurred with radioactive nucleotides by random priming or by the non-radioactive sulfonation of cytosine residues. Species identification by means of DNA hybridization is practicable even after denaturing the sample by heat or after treatment with H2O2. In case of a human sample, the sex of the donor can be determined, too.
Subject(s)
Blood Stains , DNA Probes , Hair/analysis , Species Specificity , Animals , Female , Humans , Male , Sex Determination AnalysisABSTRACT
Plant DNA was isolated from the contents of the stomach and hybridized with DNA isolates from the contents of different parts of the bowels. By this procedure we pursued the passage of the chyme. The possible predictions of this investigation concerning the shortest interval between the last meal and death will be discussed.
Subject(s)
DNA Probes , Gastrointestinal Contents/analysis , Gastrointestinal Transit , Postmortem Changes , HumansABSTRACT
A determination of sex was performed for 23 male individuals using sex-specific DNA-probe (Y) (pJA 1143) and total human DNA as DNA-probes (A). The DNA-probes were P32 marked. Applying dot-blot-hybridisation black spots are obtained, the intensity of which may be quantified by a densimeter. The ratio (A/Y) of the intensity of the spots related to total human DNA (A) and to the sex-specific DNA-probe (Y) was calculated. DNA-dilutions of one male individual were prepared in order to determine the ratio (A/Y) for different DNA-concentrations. It was evident that the deviations for the sex-specific quotients of the DNA-dilutions amounts so large-scaled as compared to the quotients of the 23 male individuals, that the method of dot-blot-hybridisation appears not to be applicable to detect an individual component of a particular spot.
Subject(s)
DNA Probes , Sex Determination Analysis , Y Chromosome , Base Sequence , Female , Humans , MaleABSTRACT
Sex-determination of a 1-year old blood-stain was realited by Dot-blot-Hybridisierung. The bloodstains were inside of a car. It was not clear, if the origin is female or male. By using total human DNA-probe (A) and a sex-specific DNA-probe (Y), (pJA 1143), labeled with P32, as soon as the calculation of the sex-specific quotient (A/Y) you could show, the bloodstains must be descended from a man.
Subject(s)
Accidents, Traffic/legislation & jurisprudence , Blood Stains , DNA Probes , Sex Determination Analysis , Female , Humans , MaleSubject(s)
Blood Stains , DNA/genetics , Polymorphism, Genetic , Polymorphism, Restriction Fragment Length , HumansABSTRACT
The temperate bacteriophage Mu transduces the 4363 bp multi-copy plasmid pBR322 at frequencies similar to those of chromosomal markers. Plasmid transducing particles contain DNA molecules of Mu DNA length. Plasmid DNA is transduced as a head-to-tail oligomer that becomes circularized in the recipient cell. The rec system of the donor strain participates in oligomer formation and the rec system of the recipient strain is required for oligomer circularization. Possible mechanisms that may explain the origin of plasmid transducing particles are discussed.
