| 1. |
- Andréasson, Hanna, et al.
(författare)
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Forensic mitochondrial coding region analysis for increased discrimination using pyrosequencing technology
- 2007
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Ingår i: Forensic Science International. - : Elsevier BV. - 1872-4973 .- 1878-0326. ; 1:1, s. 35-43
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Tidskriftsartikel (refereegranskat)abstract
- Analysis of mitochondrial DNA (mtDNA) is very useful when nuclear DNA analysis fails due to degradation or insufficient amounts of DNA in forensic analysis. However, mtDNA analysis has a lower discrimination power compared to what can be obtained by nuclear DNA (nDNA) analysis, potentially resulting in multiple individuals showing identical mtDNA types in the HVI/HVII region. In this study, the increase in discrimination by analysis of mitochondrial coding regions has been evaluated for identical or similar HVI/HVII sequences. A pyrosequencing-based system for coding region analysis, comprising 17 pyrosequencing reactions performed on 15 PCR fragments, was utilised. This assay was evaluated in 135 samples, resulting in an average read length of 81 nucleotides in the pyrosequencing analysis. In the sample set, a total of 52 coding region SNPs were identified, of which 18 were singletons. In a group of 60 samples with 0 or 1 control region difference from the revised Cambridge reference sequence (rCRS), only 12 samples could not be resolved by at least two differences using the pyrosequencing assay. Thus, the use of this pyrosequencing-based coding region assay has the potential to substantially increase the discriminatory power of mtDNA analysis.
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| 2. |
- Edlund, Hanna, et al.
(författare)
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Y chromosomal STR analysis using Pyrosequencing technology
- 2009
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Ingår i: Forensic Science International. - : Elsevier BV. - 1872-4973 .- 1878-0326. ; 3:2, s. 119-124
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Tidskriftsartikel (refereegranskat)abstract
- Analysis of Y chromosome STR markers has proven to be useful in forensic cases where the samples contain a mixture of DNA from several individuals. STR markers are commonly genotyped based on length separation of PCR products. In this study we evaluated if Pyrosequencing can be used as an alternative method for determining Y-STR variants. In total 70 unrelated Swedish males were typed for the Y chromosomal markers (DYS19, DYS389 I-II, DYS390, DYS391, DYS392, DYS393 and DYS438) using Pyrosequencing. Using the 8 markers, 57 unique haplotypes were observed with a discrimination capacity of 0.81. At four loci, the Pyrosequencing analysis revealed sequence variants. The sequence variants were found in the DYS389 II, DYS390, DYS391, and DYS393 loci in frequencies between 1.43% and 14.3%. Pyrosequencing has here been shown to be a useful tool for typing Y chromosomal STRs and the method can provide a complement to conventional forensic Y STR analyses. Moreover, the Pyrosequencing method can be used to rapidly evaluate novel markers.
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| 3. |
- Hedman, Johannes, et al.
(författare)
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A fast analysis system for forensic DNA reference samples
- 2008
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Ingår i: Forensic Science International: Genetics. - : Elsevier BV. - 1878-0326 .- 1872-4973. ; 2:3, s. 184-189
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Tidskriftsartikel (refereegranskat)abstract
- On January 1st, 2006, the Swedish legislation on obtaining DNA reference samples from Suspects and the recording of DNA profiles in databases was changed. As a result the number of samples analysed at the Swedish National Laboratory of Forensic Science (SKL) increased from about 4500 in 2005 to more than 25,000 in 2006. To meet this challenge, SKL launched a flew analysis system to create an unbroken chain, from sampling to incorporation of a profile in the national DNA database and subsequent automatic generation of digitally signed hit reports. The system integrates logistics, digital data transfer, new functions in LIMS (ForumDNA Version 4, Ida Infront AB) and laboratory automation. Buccal swab samples are secured on a FTA (R) card attached to an identity form, which is barcoded with a unique sample ID. After sampling, the police officer sends a digital request to SKL. The sample is automatically registered in LIMS and processed on delivery. The resulting DNA profiles are automatically classified according to quality using a custom-made expert system. Building the evaluation around mathematical rules makes it reproducible, standardised and minimises manual work and clerk errors. All samples are run in duplicate and the two profiles are compared within LIMS before incorporation in the database. In the first year of operation, the median time for completion of an analysis was 3 days, measured from delivery of the sample to incorporation of the profile in the national DNA database. In spite of the dramatic increase in the number of reference samples there was no backlog. (C) 2008 Elsevier Ireland Ltd. All rights reserved.
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| 4. |
- Montelius, Kerstin, et al.
(författare)
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STR data for the AmpFlSTR Identifiler loci from Swedish population in comparison to European, as well as with non-European population
- 2008
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Ingår i: Forensic Science International. - : Elsevier. - 1872-4973 .- 1878-0326. ; 2:3, s. e49-e52
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Tidskriftsartikel (refereegranskat)abstract
- The modern Swedish population is a mixture of people that originate from different parts of the world. This is also the truth for the clients participating in the paternity cases investigated at the department. Calculations based on a Swedish frequency database only, could give us overestimated figures of probability and power of exclusion in cases including clients with a genetic background other than Swedish. Here, we describe allele frequencies regarding the markers in the Identifiler-kit. We have compared three sets of population samples; Swedish, European and non-European to investigate how these three groups of population samples differ. Also, all three population sets were compared to data reported from other European and non-European populations.Swedish allele frequencies for the 15 autosomal STRs included in the Identifiler kit were obtained from unrelated blood donors with Swedish names. The European and non-European frequencies were based on DNA-profiles of alleged fathers from our paternity cases in 2005 and 2006.
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| 5. |
- Nilsson, Martina, et al.
(författare)
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Evaluation of mitochondrial DNA coding region assays for increased discrimination in forensic analysis
- 2008
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Ingår i: Forensic Science International. - : Elsevier BV. - 1872-4973 .- 1878-0326. ; 2:1, s. 1-8
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Tidskriftsartikel (refereegranskat)abstract
- There is an increasing trend to use mitochondrial DNA (mtDNA) analysis in criminal investigations where only limited amounts of DNA are available. However, analysis of the mtDNA control region has the drawback of low discrimination power, due to the lack of recombination that results from uniparental (maternal) inheritance. As a strategy to increase discrimination, a number of typing assays detecting variation in the mitochondrial coding region have been developed. In this study, several of these assays are evaluated for their discriminatory capacity using data obtained from 495 complete Caucasian mtDNA sequences. In order to add a local geographic perspective to this evaluation, we have also sequenced and analysed the entire mtDNA from 20 individuals of Swedish origin. We find that the coding region assays are very useful for resolving sequences with identical HVI/HVII regions. The best-performing coding region assay was able to discriminate 46% of the resolvable sequences, compared to 20–30% for the other coding region assays we evaluated.
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| 6. |
- Tillmar, Andreas, et al.
(författare)
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Analysis of linkage and linkage disequilibrium for eight X-STR markers.
- 2008
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Ingår i: Forensic science international. Genetics. - : Elsevier. - 1878-0326 .- 1872-4973. ; 3:1, s. 37-41
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Tidskriftsartikel (refereegranskat)abstract
- X-chromosomal short tandem repeats (X-STR) have proven to be informative and useful in complex relationship testing. The main feature of X-STR markers, compared to autosomal forensic markers, is that all loci are located on the same chromosome. Thus, linkage and linkage disequilibrium may occur. The aim of this work was to study population genetic parameters of eight X-STR markers, located in four linkage groups. We present haplotype frequencies, based on 718 Swedish males, for the four linkage groups included in the Argus X-8 kit. Forensic efficiency parameters have been calculated as well as the allelic association between the tested markers for detection of linkage disequilibrium. To study the occurrences of recombination between the loci, both Swedish and Somali families were typed. A mathematical model for the estimation of recombination frequencies is presented and applied on the family samples. Our study showed that the tested markers all have highly informative forensic values and that there is a significant degree of linkage disequilibrium between the STR markers within the four linkage groups. Furthermore, based on the tested families, we also demonstrated that two of the linkage groups are partially linked. A consequence of these findings is that both linkage and linkage disequilibrium should be accounted for when producing likelihood ratios in relationship testing with X-STR markers.
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| 7. |
- Tillmar, Andreas O, et al.
(författare)
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Genetic variation of 15 autosomal STR loci in a Somali population
- 2009
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Ingår i: Forensic Science International. - : Elsevier. - 1872-4973 .- 1878-0326. ; 4:1, s. E17-E18
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Tidskriftsartikel (refereegranskat)abstract
- Allele frequencies for 15 autosomal STR loci included in the AmpFlSTR Identifiler kit (CSF1PO, D13S317, D16S539, D18S51, D19S433, D21S11, D2S1338, D3S1358, D5S818, D7S820, D8S1179, FGA, TH01, TPOX, VWA) were obtained from the analysis of 404 individuals with Somali origin. The overall match probability for the 15 studied loci was 1 in 1.18 X 10(17) and the combined power of exclusion was 0.999997676. Deviation from Hardy-Weinberg equilibrium was observed for locus D2S1338 after correction for multiple testing. When comparing allele frequencies with five other African populations (Karamoja (Uganda), Mozambique, Tanzania and two other Somali population sample sets), only the Somali populations did not show significant differences for any of the tested loci.
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| 8. |
- Anderung, Cecilia, et al.
(författare)
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Fishing for ancient DNA
- 2008
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Ingår i: Forensic Science International: Genetics. - : Elsevier BV. - 1872-4973. ; 2:2, s. 104-107
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Tidskriftsartikel (refereegranskat)abstract
- The major problems concerning ancient DNA studies are related to the amount of extractable DNA and the precautions needed to avoid contamination. From the very first step of the analyses, the DNA extraction, these problems must be confronted. There are several extraction methods available for DNA in ancient tissue; several of them are complicated and time consuming. and none of the methods have reached an acceptance level such that they are routinely used on a widespread basis. Here we investigate the efficiency of two methods. one based on magnetic separation of the targeted molecules. and one based oil silica binding. The efficiency rate of these two on the material studied seems to be identical. The silica binding method has the benefit of relative simplicity, but the magnetic separation technique also hits advantages. For example, it is possible to reuse the extract several times for different loci, and it is possible to concentrate all extracted DNA from one locus into one PCR.
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