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At least 289 records · Page 16Linked to original sources

Allele frequencies of nine STR systems in the Flemish population and application in parentage testing.

In order to apply a set of nine STR loci in parentage testing, we performed a population genetic study on a sample of the Flemish population. Genotypes for HUMHPRTB, HUMFABP, HUMCD4, HUMCSF1PO, HUMTH01, HUMPLA2A, HUMPLA2A1, HUMF13A01, HUMCYAR04 and HUMLIPOL were determined using three triplex PCR reactions and silver staining. Allele frequencies showed no deviation from Hardy-Weinberg equilibrium. The frequency distribution agreed well with other Caucasian populations but three intermediate fragments, not previously found in Caucasians, were observed. We then resolved a series of 151 parentage disputes of which 103 were exclusions. In six cases, evidence for exclusion was obtained by only one informative STR locus out of eight for male children or out of nine for female children. These exclusions were confirmed with additional polymorphic markers. In one case of inclusion, a paternal allele expanded with one repeat unit of HUMHPRTB. This observation illustrates that STRs do not differ from other genetic systems in the fact that more than one excluding locus is required before exclusion is demonstrated.

Alleles↗

Semi-automatic DNA profiling in a Hungarian Romany population using the STR loci HumVWFA31, HumTH01, HumTPOX, and HumCSF1PO.

A population study of Hungarian Romanies was carried out for the STR loci HumVWFA31, HumTH01, HumTPOX, and HumCSF1PO. After multiplex PCR amplification semi-automatic DNA profiling was performed using an ALF DNA sequencer. At the loci investigated there was little and no evidence for departures from Hardy-Weinberg expectations and linkage equilibrium, respectively. The allele sizing accuracy of the ALF DNA sequencer was increased to a high level (99.97% on average) by applying external and internal markers. Allele frequency distributions of the STR loci, with one exception, were significantly different between the Romany and other Hungarian population databases. On the other hand, however, only small differences in frequencies of individual phenotypes were found.

Adult↗

Analysis of nine short tandem repeat (STR) loci in the Slovenian population.

A polymerase chain reaction (PCR)-based short tandem repeat (STR) system consisting of nine loci has recently been introduced in Slovenia for use in routine forensic identity testing. Fluorescently labelled PCR products were analysed using an ABI PRISM 310 Genetic Analyzer. The STR loci analysed exhibit between 6 and 14 observed alleles per locus and have a combined matching probability of 2.3 x 10(-10).

Alleles↗

Quadruplex amplification of polymorphic STR loci in a Korean population.

Multiplex PCR amplification has been useful for gene mapping with polymorphic short tandem repeat (STR) loci. We have tested the four loci D20S470, D13S325, HumFOLP23 and D10S2325 for the simultaneous typing of more than 100 unrelated Koreans. This analysis allows a single base pair resolution and rapid typing with silver staining. The allele and genotype distributions are in accordance with Hardy - Weinberg expectations. These STR loci have proven useful for forensic analysis and paternity tests in which the variable number of tandem repeat (VNTR) loci have some limitations.

Alleles↗

Y chromosome STR haplotypes: genetic and sequencing data of the Galician population (NW Spain).

Recently described Y-STR polymorphisms can be analysed as informative haplotypes which are useful in the forensic field. In order to include these systems in our forensic routine, we have carried out a population study in Galicia (NW Spain) analysing seven Y-STR polymorphisms (DYS19, DYS389-I, DYS389-II, DYS390, DYS393 and DYS385: two loci). The results were compared with other population studies. In addition various alleles for each system (except DYS385) were sequenced and the corresponding allelic ladders constructed.

Genetics, Population↗

Population genetic data on four STR loci in a Hungarian Romany population.

A population study of Hungarian Romanies was carried out on the STR loci HumLPL, HumF13B, HumFES and HumF1301. There was little evidence for association of alleles within/between the four STR systems. Allele frequency distributions were significantly different between the Romany and the previously reported Central Hungarian population databases. Population differentiation was estimated by computing F- and phi-statistics as well as frequency estimate differences of individual phenotypes for these two population samples. The results suggest that the population structure may have an effect on the interpretation of forensic DNA evidence in Hungary. Phylogenetic tree reconstruction with six populations from three major ethnic groups revealed a relatively distant genetic relationship of the Baranya Romanies with other Caucasian populations.

Alleles↗

VWA STR genotyping: further inconsistencies between Perkin-Elmer and Promega kits.

We report a simultaneous study of the VWA STR locus by the Perkin-Elmer Profiler Plus kit and the Promega GenePrint CTTv kit in a population sample from North Portugal and in 418 meiosis from family material and paternity cases. PCR amplification and genotyping were performed according to the manufacturer's instructions using ABI 377 or ABI 310 automatic sequencers. Biological kinship in family material and paternity cases was validated by the use of the STR loci D3S1358, D5S818, D7S820, D8S1179, D13S317, D18S51, D21S11, FGA, CSF1PO, TH01 and TPOX. Out of 434 unrelated individuals we found 4 inconsistencies between the genotypes obtained using each kit. No exclusions were found in the meiotic analyses. In all cases, these inconsistencies were due to an annealing failure of the Perkin-Elmer forward primer resulting in false homozygotes. Sequencing analysis revealed an A-to-T substitution at position 1631 (GenBank sequence M25858), 52 bases upstream of the first TCTA motif of the repeat region. An estimate of the null allele frequency (s) in this study is thus obtainable from the expression s = 4/(2 x 434) = 0.46%. The relatively high frequency of these discrepancies in our population demonstrates the need for caution when comparing genotype or gene frequency estimates made from amplicons produced by different primers, when evaluating apparent exclusions in paternity testing and when searching for a match between individual genetic profiles in forensic databases. Our findings are also compared with those previously reported.

Alleles↗

Allele frequencies of nine STR loci of Jewish and Arab populations in Israel.

DNA typing of nine short tandem repeat (STR) loci was carried out on unrelated Israeli Jewish and Arab individuals. All loci were highly polymorphic and the distribution of the obtained genotypes did not deviate from Hardy-Weinberg equilibrium. A comparison between Jewish and Arab population data revealed statistically significant differences in allele frequency distributions for some of the loci. The results presented in this study enable the use of these nine STR loci for forensic, identification and paternity cases in the Jewish and the Arab populations of Israel.

Arabs↗

Analysis of eight STR loci in two Hungarian populations.

A multiplex reaction for the eight STR loci D3S1358, FGA, D8S1179, D21S11, D18S51, D5S818, D13S317, D7S820 was used to generate allele frequency databases for two Hungarian population samples, Caucasians from the Budapest area and Romanies from Baranya county. During the analysis two intermediate-sized alleles and a sequence variant allele were observed at the D7S820 locus. All three types of allelic variants were found to have modifications in the same block of a (T)9 stretch located within the 3' flanking region of each allele, which may indicate a possible higher mutation rate of this (T)9 block. For the loci D3S 1358 and D7S820 the Romany population database showed departures from Hardy-Weinberg equilibrium. The forensic efficiency values for the Romany population were slightly different from those found in the Hungarian Caucasian population. Comparing the allele frequency values by G-statistic, calculating the F(ST) indices and with the pair-wise comparisons of interpopulation variance, the two Hungarian populations could be distinguished using data from the eight STR loci.

Albania↗

Signature of recent historical events in the European Y-chromosomal STR haplotype distribution.

Previous studies of human Y-chromosomal single-nucleotide polymorphisms (Y-SNPs) established a link between the extant Y-SNP haplogroup distribution and the prehistoric demography of Europe. By contrast, our analysis of seven rapidly evolving Y-chromosomal short tandem repeat loci (Y-STRs) in over 12,700 samples from 91 different locations in Europe reveals a signature of more recent historic events, not previously detected by other genetic markers. Cluster analysis based upon molecular variance yields two clearly identifiable sub-clusters of Western and Eastern European Y-STR haplotypes, and a diverse transition zone in central Europe, where haplotype spectra change more rapidly with longitude than with latitude. This and other observed patterns of Y-STR similarity may plausibly be related to particular historical incidents, including, for example, the expansion of the Franconian and Ottoman Empires. We conclude that Y-STRs may be capable of resolving male genealogies to an unparalleled degree and could therefore provide a useful means to study local population structure and recent demographic history.

Chromosomes, Human, Y↗

Discovery of genetic difference between asthmatic children with high IgE level and normal IgE level by whole genome linkage disequilibrium mapping using 763 autosomal STR markers.

The genome-wide linkage disequilibrium screen for loci associated with genetic difference between allergic and nonallergic asthma was conducted with 763 autosomal STR markers and included 190 asthmatic children. Evidence for association with differences between the two forms of asthma was observed for 36 STR markers. Marker-to-marker synergetic effect and by simulation resampling tests revealed D5S2011, D6S305, and D9S286 were important loci in allergic asthma while D6S1574, D8S1769, and D19S226 were important in nonallergic asthma. Our results show strong genetic evidence that these markers play an important role in defining allergic and nonallergic asthma and provides important candidates of susceptible genes in these two categories of asthma. This study further shows that asthma is, indeed, a heterogeneous group of underlying diseases and, although with similar clinical phenotypes, may have different clinical severities, outcomes, and need more tailor-made management.

Asthma↗

Phylogenetic analyses of Malpighiales using plastid and nuclear DNA sequences, with particular reference to the embryology of Euphorbiaceae sens. str.

We present phylogenetic analyses of Malpighiales, which are poorly understood with respect to relationships within the order, using sequences from rbcL, atpB, matK and 18SrDNA from 103 genera in 23 families. From several independent and variously combined analyses, a four-gene analysis using all sequence data provided the best resolution, resulting in the single most parsimonious tree. In the Malpighiales [bootstrap support (BS) 100%], more than eight major clades comprising a family or group of families successively diverged, but no clade containing more than six families received over 50% BS. Instead, ten terminal clades that supported close relationships between and among families (>50% BS) were obtained, between, for example, Balanopaceae and Chrysobalanaceae; Lacistemataceae and Salicaceae; and Phyllanthaceae and Picrodendraceae. The monophyly of Euphorbiaceae sens. str. were strongly supported (BS 100%), but its sister group was unclear. Euphorbiaceae sens. str. comprised two basally diverging clades (BS 100%): one leading to the Clutia group (Chaetocarpus, Clutia, Pera and Trigonopleura), and the other leading to the rest of the family. The latter shared a palisadal, instead of a tracheoidal exotegmen as a morphological synapomorphy. While both Acalyphoideae (excluding Dicoelia and the Clutia group) and Euphorbioideae are monophyletic, Crotonoideae were paraphyletic, requiring more comprehensive analyses.

DNA, Plant↗

Polysome-ribosome distribution in isogenic RC(str) and RC(rel) strains of Escherichia coli.

Study of the relative proportions of ribosomes and polysomes released by a standardized lysing procedure from isogenic RC(str) and RC(rel) strains of Escherichia coli shows that a 20-min period of amino acid starvation of RC(str) bacteria reduces the fraction of ribosomes recovered in polysomes to about 60% of its value characteristic of exponentially growing cells: A similar starvation treatment of the RC(rel) bacteria causes no appreciable reduction in the fraction of polysomal ribosomes.

Journal Article↗

Identification of ribosomal protein S7 as a repressor of translation within the str operon of E. coli.

A DNA-directed in vitro protein-synthesizing system was used to demonstrate that r protein S7 has the capacity to inhibit the translation of mRNA for the second and third gene products of the str operon (S7 and EF-G) but not for the first gene product (S12). Translation of mRNA of the last gene product in the operon (EF-Tu) is also probably not inhibited by S7. In addition, we localized the target site for S7 repressor action on the polycistronic str mRNA by examining the repressor activity of S7 in vitro using various template DNAs that contain the gene. The target site was found not to include a promoter-proximal portion of the mRNA for S12. To test for regulatory properties of S7 in vivo, we inserted the S7 gene into a plasmid vector containing the ara regulatory elements such that S7 synthesis was placed under ara control. A specific increase in S7 synthesis caused by stimulation in transcription originating from the arabinose promoter decreased the synthetic rate for EF-G but had no effect on S12 or EF-Tu synthesis.

Bacterial Proteins↗

Analysis of short tandem repeat (STR) HUMVWA in the Spanish population.

Amplification by polymerase chain reaction (PCR) of variable number of tandem repeat (VNTR) loci and subsequent typing by electrophoresis and silver staining has become a useful tool for identity testing. One viable group of genetic markers amenable to amplification by PCR is the short tandem repeat (STR) loci. A horizontal discontinuous polyacrylamide gel electrophoresis (PAGE) method was used to type the amplified products of the STR HUMVWA. Typing for VWA of 120 unrelated Spanish Caucasians was done. Six alleles were observed with frequencies in the range 0.096-0.242. The genotype distribution meets Hardy-Weinberg expectations (0.25 < P < 0.50). The heterozygosity was 73.3% and the discrimination power (DP) 0.94. Simultaneously, in a small sample of families (n = 24) no new mutations could be found.

Alleles↗

Report of the European DNA profiling group (EDNAP)--towards standardisation of short tandem repeat (STR) loci.

This paper describes a collaborative exercise intended to demonstrate whether uniformity of DNA profiling results could be achieved between European laboratories using short tandem repeat (STR) loci. Two different STRs were chosen--HUMTH01 and the AT-rich HUMACTBP2 (SE33). The former locus has only five common alleles, whereas the latter is complex and has at least 30 alleles. Laboratories were asked to test seven blood stains and to report the results to the coordinating laboratory. The exercise demonstrated that the simple STR systems such as HUMTH01 are more amenable to adoption as standard loci than complex AT-rich systems.

Alleles↗

Identification of bodies from the scene of a mass disaster using DNA amplification of short tandem repeat (STR) loci.

The accompanying paper in this issue describes work conducted during a collaborative effort to identify the victims of a mass disaster that occurred on the 19th of April 1993 near Waco, Texas. The DNA identification programme was also used partly as an exercise to further investigate the robustness and reliability of a recently developed STR quadruplex. The preceding paper provides details of the loci used and also deals with efforts to assess the applicability of STR profiling and its suitability for forensic investigations of this nature. In this paper, we present the results obtained from 61 Waco bodies. Using reference blood samples and family trees 26 positive identifications were made using a 'paternity style' analytical approach. Worked examples, representing a range of casework situations, are used to illustrate the kind of approach taken in interpretation of the data and highlight factors which affected its success. Additionally, we report on the successful application of a PCR-based gender test to 24 of the Waco bodies.

Child↗

Further validation of a quadruplex STR DNA typing system: a collaborative effort to identify victims of a mass disaster.

The relatively new, PCR-based technique of Short Tandem Repeat (STR) profiling has been used in the identification of the victims of a mass disaster. The analysis relied upon a recently developed multiplex reaction and the use of automated fluorescence technology to simulataneously analyse four tetrameric STR loci. The performance of the 'quadruplex' test was assessed by use of a collaborative study incorporating a blind trial and was demonstrated to be accurate, reliable and robust. Furthermore, the system proved to be highly successful despite the fact that many of the samples from the mass disaster scene were extremely degraded. The high success rate coupled with the discrimination power of the system enabled many severely decomposed human remains to be positively identified.

DNA↗