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M V Lareu

Publications and source records attributed to M V Lareu.

At least 37 records · Page 2Linked to original sources
PubMed1999

Robustness of the Y STRs DYS19, DYS389 I and II, DYS390 and DYS393: optimization of a PCR pentaplex.

Various technical methods were investigated with the aim of developing a multiplex system to amplify five Y-chromosome STR loci in the same PCR reaction: DYS393, DYS19, DYS390, DYS389 I and DYS389 II. A sequenced allelic ladder was constructed with previously sequenced alleles including the most common ones. A number of reamplification conditions of the allelic ladders were tested. The pentaplex was evaluated for typing using two different platforms (ABI and ALF) with promising results. However, in degraded samples non-specific artifacts were observed in the DYS393 system in the same range of sizes as the real alleles. This system can also be typed in females under relatively low stringency conditions in the PCR amplification, making this system prone to errors in critical samples. This lack of specificity can be reduced by increasing the stringency of the PCR conditions. The DYS19 ladder cannot be reamplified as stutters appear after a few reamplifications. These stutters are probably due to a 2 bp slippage induced by the presence of a TA repeat stretch in the PCR amplified fragments. Non-specific products were also noted in the DYS389 I and DYS389 II amplification, although out of the range of other alleles in this pentaplex. This newly constructed pentaplex has proved to be very useful in population genetic studies because all five Y STR markers can be loaded in the same lane of a gel with other Y STR singleplex or multiplexes. The usefulness of Y-chromosome STRs in criminal casework is especially evident in analyzing azoospermic individuals.

Artifacts↗
PubMed1999

Population data on the D1S1656 and D12S391 STR loci in Andalusia (south Spain) and the maghreb (north Africa).

Allele and genotype frequencies for two tetrameric short tandem repeat (STR) loci were determined in two population samples, from Andalusia (S Spain; n = 127) and the Maghreb (N Africa; n = 40). After denaturing polyacrylamide gel electrophoresis, 14 alleles were identified for D12S391 and 13 alleles for D1S1656. No deviations from the Hardy-Weinberg equilibrium were detected. Some statistical parameters of forensic interest (H, PD, EC) were also calculated, and the data obtained for both populations were compared. Sequencing data of several intermediate D12S391 alleles designated 17.3, 18.3, and 19.3 are also presented.

Africa, Northern↗
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

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

Genetic data on three complex STRs (ACTBP2, D21S11 and HUMFIBRA/FGA) in the Galician population (NW Spain).

The allele frequency distributions of three complex STRs, ACTBP2 (SE33), D21S11 and HUMFIBRA/ FGA in the population of Galicia were investigated. Analysis was carried out under denaturing conditions and fluorescent detection in the ALF DNA sequencer and typing was made by comparison with sequenced allelic ladders. No significant deviations from Hardy-Weinberg equilibrium were observed. No significant differences were found between our data and other Caucasian population data. ACTBP2 seems to be one of the most informative and polymorphic STRs.

Actins↗
PubMed1999

Fluorescence-based amplification of the STR loci D18S535, D1S1656 and D12S391 in a population sample from Aragon (north Spain).

Population data were generated for the STR loci D18S535, D1S1656 and D12S391 in a population sample of unrelated healthy individuals born and living in Aragon (North Spain). The three loci were amplified using a fluorescence-based PCR method and were typed automatically. No deviation from Hardy-Weinberg expectations were observed. The three loci proved to be highly discriminating and valuable polymorphisms for forensic analyses.

DNA Fingerprinting↗
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

Band shift analysis of three base-pair repeat alleles in the short tandem repeat locus D12S391.

Two hundred and sixty UK Caucasian individuals have been typed for the STR locus D12S391. Measurements of absolute band shift, relative to an allelic ladder, allowed fragments differing by one base pair to be consistently distinguished. The intermediate alleles typed from such fragments comprised approximately 5% of the total alleles observed in this study. The existence of intermediate alleles in the D12S391 locus, not included in the allelic ladder, allowed us to assess the efficacy of band shift analysis in detecting intermediate alleles on two different automated fluorescent detection platforms. The results of sequencing a sample of intermediate alleles are also presented.

Alleles↗
PubMed1998

Sequence variation of a hypervariable short tandem repeat at the D1S1656 locus.

A short tandem repeat at the D1S1656 locus was sequenced in 45 selected alleles and 13 different alleles were found which were designated according to the total number of repeats. This STR is a compound hypervariable STR consisting of blocks of (TAGR) repeats with a basic sequence structure (TAGA)4(TGA)0-1(TAGA)6-16(TAGG)0-1(TG)5. The presence of a TGA, probably due to an A deletion in the fifth TAGA repeat leads to intermediate a.3 alleles. Population data showed that this is a highly polymorphic STR with a heterozygosity of more than 0.89. This fact together with its simple structure and small size (129-168 bp) makes this STR one of the most interesting DNA polymorphisms for forensic and genetic purposes.

Alleles↗
PubMed1998

Sequence variation of a variable short tandem repeat at the D18S535 locus.

A short tandem repeat in the D18S535 locus was sequenced in 25 selected alleles. A total of 8 different alleles were found which can be designated according to the total number of repeats. This STR is a simple hypervariable STR consisting of blocks of (GATA) repeats with a basic sequence structure (GATA)1(GACA)1(GATA)1 (GAT)1(GATA)9-16. Population data showed that this is a highly polymorphic STR with a heterozygosity of more than 0.80, a simple structure and small size (130-158 bp) which makes this an interesting DNA polymorphism for forensic and genetic purposes.

DNA↗
PubMed1998

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↗
PubMed1998

Linkage analysis in a large Spanish family with X-linked retinitis pigmentosa: phenotype-genotype correlation.

X-linked retinitis pigmentosa (XLRP) accounts for 10-25% of RP families and causes the most severe form of the disease in terms of onset and progression. Although three different loci (RP3, RP2 and RP15) have been proposed on the short arm of the X-chromosome by linkage analysis, RP3 represents the disease locus in the majority of XLRP families. The identification of female carriers of X-linked RP is important for genetic counselling. The presence of fundus and electroretinogram (ERG) abnormalities have been reported to be as high as 87 and 90%, respectively. However, in clinical practice it has not always been possible to know the carrier state of females at risk. Thirty-five members of a Spanish family with X-linked RP were evaluated by linkage analysis using nine polymorphic markers (CYBB, DXS1110, M6, DXS6679, DXS1068, DXS1058, MAOA, MAOB and DXS6849) that map to the X-chromosome region Xp21.1 to Xp11.3, in an attempt to determine the carrier state of these females at risk. It was possible to establish that a RP3 mutation is, most likely, segregating in this family.

Adolescent↗
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

Rapid and enhanced detection of mitochondrial DNA variation using single-strand conformation analysis of superposed restriction enzyme fragments from polymerase chain reaction-amplified products.

A strategy is described for detecting mitochondrial (mt) DNA variation which permits rapid and straightforward screening for forensic purposes. The method is based on the selection of fragments with adequate length for performing single strand conformation polymorphism (SSCP) analysis selecting a set of restriction enzymes (RE) which yield fragments with prefixed lengths. After digestion of mtDNA by the appropriate enzyme or set of enzymes, SSCP analysis is performed in a semiautomatic electrophoretic system using a silver staining detection method. The conformational changes due to single mutations were therefore found not to change the electrophoretic protocol but to change the relative position of the mutations within the fragment. The discrimination power of this method is estimated to be 90% when two restriction enzymes (MspI and HinfI) are used, but it is considerably higher when other enzymes are added.

DNA Mutational Analysis↗
PubMed1996

Sequence variation of a hypervariable short tandem repeat at the D12S391 locus.

A short tandem repeat (STR) in the D12S391 locus was sequenced in more than 40 individuals. Twenty different alleles were found and these could be grouped into 12 allelic classes in accordance with the total number of repeats. This is a compound STR consisting of blocks of (AGAT) and (AGAC) repeats with basic sequence structure (AGAT)8-17(AGAC)6-10(AGAT)0-1. Whereas smaller alleles (15-18) have variation limited to the (AGAT) unit, in larger alleles the complexity is greater with variation in the number of tandem arrays in the two motifs (AGAT) and (AGAC). Population data showed that this is a highly polymorphic STR with a heterozygosity of more than 0.9. This fact, together with its simple structure, makes this STR an interesting DNA polymorphism for forensic and genetic purposes.

Alleles↗
PubMed1996

Effect of environmental factors on PCR-DNA analysis from dental pulp.

This study was designed to observe the results of DNA typing on teeth subjected to aging, different temperatures and various environmental factors. A total of 570 teeth were studied. The study included the analysis of the PCR-based polymorphisms HLA DQA1, D1S80, HUMTH01, HUMFES/FPS and the XY homologous gene amelogenin. In general the best results were obtained with the XY homologous gene amelogenin, followed by the two STRs studied (HUMTH01 and HUMFES/FPS). The small fragment sizes and the method of detection used after PCR amplification are the main factors explaining this fact. In general, teeth submerged in water gave the poorest results. Teeth exposed to outdoor conditions provided better results than teeth buried in sand or soil, but even in these cases good results were obtained. Up to 4 degree C, temperature had only a slight influence on the results. Positive results were obtained in most cases at high temperatures (400 degrees C for 2 min) which are rarely reached in practical casework. Positive typing results for the XY homologous gene amelogenin and the STRs were obtained from teeth 10-30 years old. The usefulness of dental pulp for identification purposes is exemplified in some actual cases.

DNA Fingerprinting↗
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↗