Biomedical subjects

M Schürenkamp

Publications and source records attributed to M Schürenkamp.

15 recordsLinked to original sources

PubMed2004

The GEDNAP blind trial concept part II. Trends and developments.

This article presents a review of the developments in the GEDNAP blind trials over the period covering the past 10 years (1993-2003), demonstrating the changing approach to DNA investigations in the European community as a whole. The results of the trials also identify the most common types of error encountered which can also occur during routine DNA typing and ways of recognising such errors are suggested.

Clinical Trials as Topic↗

PubMed2001

The evidential value of STRs. An analysis of exclusion cases.

In this study, a total of 191 cases with STR exclusions out of 591 paternity cases were analysed using 2 STR sets, i.e. (set a) 5 STRs in 462 cases with 150 exclusions and (set b) 9 STRs in 129 cases with 41 exclusions. Set (a) was associated with four exclusions on average while set (b) showed five exclusionary loci on average. Double exclusions were observed in 18 cases and further elaborated. Of these, 2 ended up with probabilities of paternity of 0.1% and 0.4%, respectively and with a random occurrence of the hypothesis "mutation" of 1:20,000 and 1:50,000, respectively, while all other cases were associated with much lower frequencies. The conclusion is that the evidential value of a set of highly polymorphic STRs applied in paternity cases is usually extremely high.

Genetic Markers↗

PubMed1999

D18S535, D1S1656 and D10S2325: three efficient short tandem repeats for forensic genetics.

Three short tandem repeat (STR) polymorphisms characterized by PCR product length < 175 bp were investigated. D18S535 and D1S1656 contained a 4 bp unit as basic repeat motif, D10S2325 a 5 bp unit. The heterozygosity rates were 0.76 (D18S535), 0.88 (D10S2325) and 0. 90 (D1S1656), leading to a combined discrimination power of 0.9999. In contrast to D10S2325 and D18S535, which showed a homogeneous repeat array without any variation in the repeat motifs, repeat length and sequence variation was found for D1S1656. Robust typing results could be observed for all three STRs using highly degraded DNA.

Alleles↗

PubMed1999

Human Y-chromosomal STR haplotypes in a Kurdish population sample.

In an Iraqi Kurdish population sample (n = 101), seven polymorphic STR loci of the Y-chromosome (DYS19, 389, 390, 391, 392, 393, and DXYS156-Y) were typed, with DYS389 being subtyped for its four segments. The haplotype diversity was 97.83% and 82 different haplotypes were observed. The Kurds shared some Y-types with neighbouring south Turks but strikingly few with Germans: it is 20-30 times more likely to find a sequence match in a random pair of Kurds than in a random Kurd-German pair.

Ethnicity↗

PubMed1998

Hungarian population data for six STR loci.

Population genetic studies were carried out on a South Hungarian population (n = 111 individuals). The short tandem repeat (STR) systems Hum VWA, HumTH01, HumF13B, HumCD4, HumFES and HumFIBRA (FGA) were investigated by PCR amplification. All loci met Hardy-Weinberg expectations.

Alleles↗

PubMed1998

Tetranucleotide STR system D8S1132: sequencing data and population genetic comparisons.

In the present investigation of the D8S1132 locus 31 selected alleles were sequenced. In total there were 9 distinguishable alleles found to increase in size by regular 4 bp increments from 134 to 170 bp with a repeat array following the pattern (TCTA)n TCA (TCTA)n. One-third of the sequenced alleles exhibited an altered repeat sequence TCTG TCTA at the 3' flanking region of the repeat array. A nomenclature for the designation of D8S1132 alleles is proposed on the basis of this sequence data and in accordance with the ISFH recommendations. The allele distribution of the D8S1132 locus has been investigated in three German populations (Halle-, Münster-, and Wiesbaden area) with frequencies ranging from 0.004 to 0.24. No deviation from Hardy-Weinberg equilibrium could be observed. The heterozygosity was 0.83 and the discrimination power 0.96 for the Halle population.

Alleles↗

PubMed1998

Y-chromosome STR haplotypes in an Italian population sample.

Seven Y-chromosome STRs were investigated in a male population sample from the Modena area by means of one quadruplex reaction (systems DYS19, DYS390, DYS391, DYS393), one duplex reaction (systems DYS389-II, DYS392) and two single PCR reactions (DXYS156 and DYS389-I/II). In 100 males, 71 different haplotypes could be observed, 57 of which were seen only once. The haplotype diversity/discrimination index is 0.97. The resulting database could be used for routine forensic application like paternity testing and stain investigation.

Alleles↗

PubMed1997

Sequence polymorphism at the tetranucleotide repeat of the human beta-actin related pseudogene H-beta-Ac-psi-2 (ACTBP2) locus.

The tetranucleotide repeat polymorphism in the human beta-actin related pseudogene H-beta-Ac-psi-2 (ACTBP2) locus has become a widely used short tandem repeat (STR) system in paternity testing and human identification. The discrimination index of this locus has been reported to be as high as 99.65%. To study the overall variability of this locus, 222 alleles were sequenced in our laboratory. Here, we report the sequences of the 102 different alleles observed. In addition to the length polymorphism, up to ten different sequence variants for single fragment lengths have been detected.

Actins↗

PubMed1997

Genetic variation at five STR loci in subpopulations living in Turkey.

Five short tandem repeat (STR) systems HumVWA, HumTH01, HumCD4, HumF13B and HumFES were investigated in 2 subpopulations living in Turkey (Laz Turks and Kurds). The population genetic data were compared to a Turkish population sample from the Adana area. A closer genetic relationship was found to the Laz Turks than to the Kurdish sample which was also confirmed by phylogenetic tree reconstruction with seven populations from three major ethnic groups (Caucasian, Asian and African). In contrast to the Laz and Adana populations the Kurdish sample showed relatively low heterozygosity values and deviations from Hardy-Weinberg equilibrium in four of the five systems.

Alleles↗

PubMed1996

A highly variable STR at the D12S391 locus.

A total of 103 fragments in the STR D12S391 locus were sequenced. 24 different alleles were found which can be grouped into 12 allelic classes based on the total number of repeats. The structure of this compound STR consists of blocks of (AGAT) and (AGAC) repeats with a consensus structure (AGAT)8-17 (AGAC)6-10 (AGAT)0-1. Whereas shorter alleles only have (AGAT) repeats, > 225 bp alleles are more complex, having two motifs (AGAT) and (AGAC). Population data showed that this to be a highly polymorphic STR with a heterozygosity of 0.9. This fact together with its simple structure make this STR very suitable for forensic and genetic purposes.

Alleles↗

PubMed1996

The STR systems HumVWA and HumACTBP2 in a Hungarian population.

Allele frequencies of the Short tandem repeat systems HumVWA and HumACTBP2 were determined from 105 unrelated individuals from the area of Szeged, Hungary. A total of 8 alleles was detected for VWA, and 23 alleles were found for ACTBP2. In both systems no deviations from Hardy-Weinberg equilibrium were observed. A comparison of the Hungarian and German frequency profiles revealed significant differences at both STR loci.

Alleles↗

PubMed1995

Evaluation of an ACTBP2 ladder composed of 26 sequenced alleles.

A total of 90 alleles found in white Caucasians from North-West Germany were sequenced and 26 alleles chosen to construct a uniform and reliable allelic ladder for the STR system ACTBP2 (SE33). In addition 3 new aspects concerning the sequence structure were observed. Population studies were carried out on white Caucasians (n = 278) from North-West Germany using the new improved ladder. A total of 24 alleles and 14 "interalleles" were found and reproducible results obtained. No significant deviation from Hardy-Weinberg-equilibrium could be observed.

Alleles↗

PubMed1995

HumFES/FPS and HumF13B: Turkish and German population data.

The allele distribution of two STRs has been investigated in two populations, i.e. Turks (n = 203/200) and Germans (n = 414/402). The Turkish population showed 11 alleles in HumFES/FPS and 6 alleles in HumF13B while the German population had 9 (FES) and 8 (F13B) alleles respectively. Although the frequency profiles looked quite similar in both populations, there exist significant differences mainly due to alleles 8 and 10 (F13B) and allele 12 (FES). Four variant alleles have been sequenced and are described. Investigation of 368 (FES)/372 (F13B) meioses revealed no new mutations.

DNA↗

PubMed1992

DNA extraction from mixtures of body fluid using mild preferential lysis.

A modification to the DNA extraction method "preferential lysis" (Gill et al. 1985) is proposed which can be applied to DNA mixtures of vaginal cells and spermatozoa. In mixtures with a low sperm content the further loss of sperm DNA caused by the extraction can be avoided by using "mild preferential lysis". Amplification by PCR (polymerase chain reaction) then yields sufficient DNA to be able to identify both components in the mixture.

Body Fluids↗

PubMed1989

[Evaluation of unusual band patterns in immunochemophoresis].

The occurrence of unusual band patterns in the protein systems Gc, F XIII B and PLG is described. During the routine investigation of these systems in paternity, identity and criminal cases, several examples of alterations or additions to the normal band patterns have been observed. This was particularly noticeable in post mortem samples, stored liquid blood samples and blood stains. A connection between alterations in the form due to charge changes and changes to the isoelectric point from ageing of blood samples is demonstrated.

Blood Protein Electrophoresis↗