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A Kratzer

Publications and source records attributed to A Kratzer.

15 recordsLinked to original sources
PubMed2005

Y-chromosome STR haplotypes in a population sample from Switzerland (Zurich area).

Allele frequencies and haplotypes for 12 Y-chromosome STR loci (DYS19, DYS385a/b, DYS389I, DYS389II, DYS390, DYS391, DYS392, DYS393, DYS437, DYS438 and DYS439), included in the PowerPlex Y multiplex kit, were determined for a Swiss population sample of 150 male individuals. The gene diversities for the different loci were in the same range as shown for other European Population samples. The haplotype diversity was 0.9922. Pairwise haplotype analysis showed no significant differences in comparison with other European Population samples.

Chromosomes, Human, Y↗
PubMed1999

Results of collaborative study regarding the standardization of the Y-linked STR system DYS385 by the European DNA Profiling (EDNAP) group.

Y-chromosome linked short tandem repeat (STR) loci are inherited as a closely linked haplotype, which appears to remain stable in a given paternal lineage over many generations. In forensic cases, Y-linked STRs are particularly useful for the identification of human remains as well as in rape cases with mixed male/female stain samples. DYS385 is derived from tandemly duplicated segments of the Y chromosome thus giving rise to two fragments of variable length which do not behave like alleles but genotypes. The European DNA Profiling (EDNAP) group has carried out a collaborative exercise among 14 participating laboratories using DYS385 for typing of five unknown bloodstains and a control sample. Furthermore, population data from eight different European countries with samples sizes between 91 and 150 male individuals were collected. The results confirm previous observations that DYS385 is one of the most informative Y-linked STR loci. It could also be demonstrated that reproducible results can be obtained independently from the electrophoretic separation and detection methods used. Thus DYS385 may serve as a useful complementation to the routinely used autosomal STR systems in special cases.

Blood Protein Electrophoresis↗
PubMed1999

[Species diagnosis of a tissue using the polymerase chain reaction].

The unambiguous identification of a biological specimen can deliver invaluable evidence to solve criminal cases. In this case the origin of a heart had to be clarified. Using the polymerase chain reaction technique and species-specific primer pairs for two genes it was clearly shown that this tissue was not from a human but from a pig.

Animals↗
PubMed1998

Report of the European DNA Profiling Group (EDNAP)--an investigation of the hypervariable STR loci ACTBP2, APOAI1 and D11S554 and the compound loci D12S391 and D1S1656.

This paper describes the results of three collaborative exercises which continues the EDNAP theme to explore whether uniformity of DNA profiling results could be achieved between European laboratories using STRs. In an earlier exercise, complex hypervariable AAAG-repeat STR loci were investigated, but reproducibility was found to be poor because of the variation of techniques used by participating laboratories. In the exercise reported here, an internal allelic ladder composed of ACTBP2 and D11S554 fragments was distributed. This ladder was used to size ACTBP2 analysed by a "singleplex" PCR amplification and D11S554 combined with APOAI1 in a separate "duplex" reaction. Laboratories were asked to test 7 blood stains, one of which was a known control, and to report the results to the co-ordinating laboratory. The exercise demonstrated that ACTBP2 showed good reproducibility between laboratories, whereas further testing would be needed to validate APOAI1 and D11S554 for interlaboratory comparisons. In separate exercises, the simple loci D12S391 and D1S1656 were tested; both of these showed excellent reproducibility between laboratories.

Alleles↗
PubMed1998

Forensic validation of the short tandem repeat HUMACTBP2 using capillary electrophoresis.

Experiments were performed to evaluate the forensic identification of the short tandem repeat (STR) HUMACTBP2 (human beta-actin-related pseudogene) using automated fluorescence-based capillary electrophoresis. The HUMACTBP2 is a complex tetranucleotide STR locus with more than 32 alleles in the range of 202-323 bp. The reproducibility of genetic typing using a fluorescent labeled allelic ladder was determined by comparison of the calculated fragment size after consecutive (within-day) and nonconsecutive (day to day) injection. The maximum variation in size (window) observed for any allele was 0.23 bp for the within-day and 0.8 bp for the day-to-day precision. Furthermore, it is possible to achieve a 1 bp resolution, the precision of the reproducibility assays being about 99.95%. Sixty blood samples and twenty stains were typed with both automated fluorescent sequencer ABI 373A and ABI 310. Identical genotypes were obtained with both techniques and the ABI 310 seemed to be more sensitive than the ABI 373A. A population sample of 197 unrelated individuals from southwest Switzerland was analyzed and the genotype frequencies observed were similar to those reported by others. Thirty-one alleles and 126 genotypes were found. The observed heterozygosity was 0.934. Mixtures from two different blood samples varying in their ratio were typed and the minor fraction was detectable to about 1:10. The practical usefulness of the HUMACTBP2 is illustrated by analyzing casework samples. This validation study proves the usefulness of the HUMACTBP2 locus in forensics and the detection efficiency using fluorescent capillary electrophoresis.

Actins↗
PubMed1997

Report of the European DNA profiling group (EDNAP): an investigation of the complex STR loci D21S11 and HUMFIBRA (FGA).

This paper describes a collaborative exercise which was intended to demonstrate whether uniformity of DNA profiling results could be achieved between European laboratories using two complex short tandem repeat (STR) loci. The loci D21S11 and HUMFIBRA (FGA) were chosen because they are commonly used by different European laboratories. D21S11 has approximately 14 common alleles (f > 0.001), whereas HUMFIBRA has 19 common alleles. Laboratories were asked to test seven blood stains, one of which was a known control, and to report the results to the coordinating laboratory. The exercise demonstrated that complex STRs were amenable to standardisation.

Alleles↗
PubMed1997

[Forensic hematology genetics--paternity testing].

In Switzerland paternity investigations are carried out using DNA analysis only since 1991. DNA patterns are inherited and only with the exception of genetically identical twins they are different in everyone and therefore unique to an individual. Hence DNA-systems are an excellent tool to resolve paternity disputes. DNA polymorphisms used for paternity diagnosis are length polymorphisms of the highly polymorphic VNTR loci [variable number of tandem repeats]. The most frequently applied systems are the DNA single locus systems. In addition to the DNA single locus systems the application of PCR (PCR = polymerase chain reaction) based DNA systems has increased particularly in difficult deficiency cases or in cases where only small evidential samples or partially degraded DNA are available. Normally four independent DNA single probes are used to produce a DNA profile from the mother, the child and the alleged father. A child inherits half the DNA patterns from its mother and the other half from its true biological father. If an alleged father doesn't possess the paternal specific DNA pattern in his DNA profile he is excluded from the paternity. In case of non-exclusion the probability for paternity is calculated according to Essen-Möller. When applying four highly polymorphic DNA single locus systems the biostatistical evaluation leads always to W-values exceeding 99.8% [= required value for positive proof of paternity]. DNA analysis is currently the best available method to achieve such effective conclusions in paternity investigations.

Blood Group Antigens↗
PubMed1996

Report on the third EDNAP collaborative STR exercise. European DNA Profiling Group.

This report describes an inter-laboratory exercise completed on behalf of the European DNA Profiling (EDNAP) group. The exercise is one in a series designated to identify STR loci which could be used for harmonisation between participating European forensic science laboratories. Participants were asked to identify the alleles present in five bloodstains at the STR loci HUMTHO1 and HUMVWFA31/A. Two of the stains were prepared from mixtures of two different blood samples. There were no special instructions and each laboratory was requested to use the methodology normally employed for crime case investigations. All participating laboratories achieved the same results for both loci. In addition, the laboratories were also requested to report the results obtained from any other loci which would normally be used in crime case investigations. A comparison of these results showed some inter-laboratory variation.

Alleles↗
PubMed1989

[Assessment of disputed identity of blood alcohol samples using DNA fingerprinting].

DNA fingerprinting is a perfect tool for investigating the identity of disputed blood by alcohol samples extracted. However, blood samples stored at an ambient temperature for longer periods can show considerable degradation of high-molecular DNA, diminishing the value of fingerprint investigation because of loss of the less frequent bands formed by the longer DNA fragments. Addition of the complexing agent EDTA can retard this degradation. Determination of the sex with DNA probes in the blood alcohol sample increases confidence in the investigation.

Alcoholic Intoxication↗
PubMed1988

Postmortem stability of DNA.

High-molecular-weight DNA was recovered postmortem in sufficient quantities from various human organ tissues as well as from blood, although not all organs were equally well suitable. Good DNA stability was found in brain cortex, lymph nodes and psoas muscle over a period of three weeks postmortem. Spleen and kidney showed good DNA stability up to five days postmortem but after longer periods, rapid degradation was observed. Yields of DNA from blood were not consistent because of the non homogeneity of samples. Blood clots were rich with DNA. Generally, the amount of degraded DNA correlated directly with the duration of the postmortem period. However in some cases, DNA degradation was already prominent after a short period. However in some cases, DNA degradation was already prominent after a short period. Case histories showed that high environmental temperature at the site of death and/or infectious diseases prior to death were the main factors for rapid autolysis. Gradual disappearance to complete loss of the long fragments (15-23 kb) was observed in DNA fingerprinting using the minisatellite probe 33.15. No extra-bands were noted, thus excluding erroneous conclusions. However, evidentiary value of older samples was lower.

Cerebral Cortex↗
PubMed1988

Polymorphism of alpha-1-antitrypsin (Pi) in the Swiss population determined by isoelectric focusing with an immobilized pH gradient.

The distribution of the phenotypes of alpha-1-antitrypsin (Pi) was investigated in a Swiss population sample of 1,148 unrelated individuals using isoelectric focusing with a immobilized pH gradient. A short focusing period of only 2 h using high-voltage is an additional asset of this modified method. All common as well as the rarer phenotypes were reliably detected. However, detection of Pi M4 required a narrower pH range as chosen for routine work. The allele frequencies found were: PiM1:0.7121; PiM2:0.1381; PiM3:0.0976; PiS:0.0383; PiZ:0.0113; PiVar(I, N, V.Vdon):0.0026.

Alleles↗