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  • 1.
    Aarts, B.
    et al.
    Netherlands Forensic Institute, Biological Traces and DNA, The Hague, Netherlands.
    Kokshoorn, B.
    Netherlands Forensic Institute, Biological Traces and DNA, The Hague, Netherlands.
    Mc Kenna, L.G.
    Forensic Science Ireland, DNA department, Dublin, Ireland.
    Drotz, W.
    Swedish National Forensic Centre, DNA department, Linköping, Sweden.
    Ansell, Ricky
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, Faculty of Science & Engineering. Swedish National Forensic Centre, DNA department, Linköping, Sweden.
    van Oorschot, R.A.
    Office of the Chief Forensic Scientist, Victoria Police Forensic Services Department, Macleod- Victoria, Australia.
    Kloosterman, A.D.
    Netherlands Forensic Institute, Biological Traces and DNA, The Hague, Netherlands.
    DNActivity: International cooperation in activity level interpretation of forensic DNA evidence.2015In: Abstract book, 7th European Academy of Forensic Science, EAFS, Prag, Tjeckien, 2015., 2015, 555- p.Conference paper (Other academic)
    Abstract [en]

    Questions posed to expert witnesses by the legal community and the courts are expanding to include not just those relating to source level (i.e. ‘who is the donor of the trace?’) but also those relating to activitity level (i.e. ‘how did the DNA get there?’). The answers to these questions are usually formulated as the probability of the evidence under alternative scenarios. As activity level questions are part of investigative and legal considerations it is of paramount importance that expert witnesses are provided with knowledge and tools to address these questions.

    To answer such questions within a probabilistic framework, empirical data is needed to estimate probabilities of transfer, persistence and recovery of DNA as well as background levels of DNA on everyday objects. There is a paucity of empirical data on these topics, but the number of studies is increasing both through in-house experiments and experimental data published in international scientific journals.

    Laboratories that conduct such studies all use different experimental setups, trace recovery strategies and techniques and DNA analysis systems and equipment. It is essential for the forensic genetics community in general to establish whether the data generated by different labs are in concordance, and can therefore be readily used by the forensic community.

    Moreover, if existing data and data generated from future experiments are made available to the (forensic) community, knowledge is needed on the key factors that underlie potential interlaboratory variation.

    The aims and objectives of this ENFSI Monopoly 2013 project are to conduct a study of methodologies and data from different laboratories and to assess the comparability of the scientific data on transfer, persistence and recovery of DNA. This comparison will allow us to identify key factors that underlie potential variation. This information will be used to setup guidelines to enable sharing and database-storage of relevant scientific

    data. This will improve the ability of forensic scientists and other professionals of the Criminal Justice System to give evidence-based answers to questions that relate to the activity level of the crime under investigation.

  • 2. af Forselles, J.
    et al.
    von Eckardstein, S.
    Stegeryd, Y.
    Svanström, M.
    Ansell, Ricky
    Linköping University, Department of Physics, Chemistry and Biology, Molecular genetics . Linköping University, The Institute of Technology.
    Integration of rape case related information in the electronic communication between the Swedish police and the forensic laboratory2009In: Book of Abstracts, 2009, 126- p.Conference paper (Refereed)
  • 3. Albinsson, L.
    et al.
    Ansell, Ricky
    Linköping University, Department of Physics, Chemistry and Biology, Molecular genetics . Linköping University, The Institute of Technology.
    Drotz, Weine
    Swedish National Laboratory of Forensic Sciences, Linköping.
    Single DNA analysis approach of crime scene samples2009In: Book of Abstracts, 2009, 142- p.Conference paper (Refereed)
  • 4.
    Albinsson, L.
    et al.
    Swedish National Forensic Centre - NFC, Linköping, Sweden.
    Hedman, J.
    Swedish National Forensic Centre - NFC, Linköping, Sweden.
    Ansell, Ricky
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, Faculty of Science & Engineering. Swedish National Forensic Centre - NFC, Linköping, Sweden.
    Mixed DNA profiles from single-donors2015In: Abstract book, 7th European Academy of Forensic Science, EAFS, Prag, Tjeckien, 2015, 2015, 538- p.Conference paper (Other academic)
    Abstract [en]

    Mosaicism and chimerism in individuals can complicate the interpretation and even lead to misinterpretation of DNA profiles in forensic casework. If a person has different DNA profiles in different tissue types, i.e. a true chimaera, wrongful exclusions can be made. Additionally, mixed chimaeras can have DNA profiles that may be mistaken for mixtures. We have set-up automatic DNA databasing processes to handle atypical single-donor DNA profiles, i.e. profiles having one or several “extra” alleles.

    Studying all reference samples analysed at NFC from 2006 until spring 2014, 2‰ of the samples showed atypical DNA profiles. To be able to set routines for handling these DNA profiles, each one was manually searched in CODIS with adjusted settings, to evaluate the frequency of false-positive hits. To tag these profiles in LIMS a new result status was implemented. Additionally, all such DNA profiles must be confirmed by analysing at least two discrete samples. In LIMS, the results are manually recorded to compose of all alleles from the samples from a suspect, i.e. containing most possible genetic information. LIMS automatically categorises the atypical DNA profiles with a special CODIS index, called “Multi-allelic offender”. The first time an atypical profile is searched, the matches are manually investigated. If a match is false, its disposition will be set to “no match” to prevent this from occurring in future searches. Automatic searches will then be performed in every day routine with moderate stringency, allowing the atypical DNA profile to match either a genotype or a mixture. If the match is true, a match-report will be created and sent to the police from the LIMS.

     

  • 5.
    Albinsson, L.
    et al.
    Swedish National Laboratory of Forensic Science, Linköping.
    Hedman, J.
    Swedish National Laboratory of Forensic Science, Linköping.
    Ansell, Ricky
    Linköping University, Department of Physics, Chemistry and Biology, Molecular genetics . Linköping University, The Institute of Technology.
    Verification of alleles by using peak height thresholds and quality control of STR profiling kits2011In: Forensic Science International: Genetics, Supplement Series, ISSN 1875-1768, Vol. 3, no 1, e251-e252 p.Article in journal (Refereed)
    Abstract [en]

    In the autumn of 2010 SKL performed in-house validation of PowerPlex ESX 16 System (Promega). As the validation showed that very low amounts of DNA (∼10 pg) may provide correct allele callings (peaks above 50 rfu), we investigated the linear range, i.e., the interval of DNA amounts where a profile is well balanced and does not contain drop-outs and/or drop-ins. The linear range as indicated by our results is approximately from 0.5 ng (manufacturer's recommendation) to 2.0 ng of DNA. As minute DNA amounts may be detected using the kit, extra care needs to be taken not to report a contaminant allele as a part of the correct profile. A way to verify the correctness of a single donor profile in routine analysis, without using duplicate analysis, is to use conservative peak height thresholds. We determine STR marker specific peak height thresholds for each new lot of DNA profiling kits, based on the results from three different tests: heterozygote balance, signal intensity and repeatability, and PCR inhibitor tolerance. The tests also serve to verify the quality of the kit lot. Generally, the peak height thresholds vary between 200 and 250 rfu for heterozygote alleles, with doubled values used for homozygotes.

  • 6.
    Albinsson, L.
    et al.
    Swedish National Laboratory of Forensic Science (SKL), Linköping, Sweden.
    Hedman, J.
    Swedish National Laboratory of Forensic Science (SKL), Linköping, Sweden.
    Ansell, Ricky
    Linköping University, Department of Physics, Chemistry and Biology, Molecular genetics . Linköping University, The Institute of Technology.
    Verification of alleles by using peak height thresholds and quality control of STR profiling kits2011In: Book of Abstracts, 2011, 134- p.Conference paper (Refereed)
    Abstract [en]

    In the autumn of 2010 SKL performed in-house validation of PowerPlex ESX 16 System (Promega). As the validationshowed that very low amounts of DNA (< 10 pg) may provide correct allele callings (peaks above 50 rfu),we investigated the linear range, i.e., the interval of DNA amounts where a profile is well balanced and doesnot contain drop-outs and/or drop-ins. The linear range as indicated by our results is approximately from 0.5ng (manufacturer’s recommendation) to 2.0 ng of DNA. Profiles generated by less than 0.5 ng contained intralocus imbalances and/or drop-outs. Above 2.0 ng “bleed through” occurs due to overload of template-DNA.A way to verify the correctness of a profile, without knowing anything about the condition of the template-DNA, is to use peak height thresholds adjusted to each marker and batch of kits used. SKL performs a qualitycontrol and adjust thresholds for each batch of kits. Three main tests are performed; detection limit, inhibitortolerance and signal repeatability. The detection limit is examined to identify at which concentration intralocus imbalances and drop-outs start to increase. The ability to overcome inhibition is checked by analysingvarying amounts of blood extracted with Chelex. Finally a set of replicates of control DNA is amplified (0.5 ngtemplate-DNA) to calculate the mean peak height and standard deviation at each locus. Generally, the peakheight thresholds vary between 200 and 250 rfu for heterozygote peaks. To verify allelic peaks below the setpeak height thresholds, SKL uses consensus analysis.

  • 7.
    Albinsson, Linda
    et al.
    Biologienheten SKL.
    Hedman, Johannes
    Biologienheten SKL.
    Ansell, Ricky
    Biologienheten SKL.
    SKL byter DNA-kit2011In: Kriminalteknik, no 1, 4-5 p.Article in journal (Other (popular science, discussion, etc.))
  • 8.
    Albinsson, Linda
    et al.
    Swedish National Laboratory of Forensic Science (SKL), Linköping, Sweden.
    Norén, Lina
    Swedish National Laboratory of Forensic Science (SKL), Linköping, Sweden.
    Hedell, Ronny
    Swedish National Laboratory of Forensic Science (SKL), Linköping, Sweden.
    Ansell, Ricky
    Linköping University, Department of Physics, Chemistry and Biology, Molecular genetics. Linköping University, The Institute of Technology.
    Swedish population data and concordance for the kits PowerPlexÒ ESX 16 System, PowerPlexÒ ESI 16 System, AmpFlSTRÒ NGMTM, AmpFlSTRÒ SGM PlusTM and Investigator ESSplex2011In: Forensic Science International: Genetics, ISSN 1872-4973, Vol. 5, no 3, e89-e92 p.Article in journal (Other academic)
    Abstract [en]

    The European Standard Set of loci (ESS) has been extended with five additional short tandem repeat (STR) loci following the recommendations of the European Network of Forensic Science Institutes (ENFSI) and the European DNA Profiling Group (EDNAP) to increase the number of loci routinely used by the European forensic community. Subsequently, a new extended Swedish population database, based on 425 individuals, has been assembled using the new STR multiplex kits commercially available.

    Allele frequencies and statistical parameters of forensic interest for 15 autosomal STR loci (D3S1358, TH01, D21S11, D18S51, D10S1248, D1S1656, D2S1338, D16S539, D22S1045, vWA, D8S1179, FGA, D2S441, D12S391 and D19S433) were obtained from the analysis of the PowerPlex® ESX 16 System kit (Promega Corporation, USA). According to the data no evidence of deviations from Hardy–Weinberg equilibrium was found. The observed heterozygosity varies between 0.755 (TH01) and 0.892 (D1S1656). The power of discrimination was smallest for D22S1045 (0.869) and largest for D1S1656 (0.982) while the power of exclusion was smallest for TH01 (0.518) and largest for D1S1656 (0.778).

    A concordance study was performed on the five amplification systems: PowerPlex® ESX 16 System, PowerPlex® ESI 16 System (Promega Corporation, USA), AmpFlSTR® NGM™, AmpFlSTR® SGM Plus™ (Applied Biosystems, USA) and Investigator ESSplex (Qiagen, Germany) to reveal null alleles and other divergences between the kits. For the 425 DNA profiles included, AmpFlSTR® NGM™ revealed two null alleles, AmpFlSTR® SGM Plus™ revealed one, and Investigator ESSplex revealed a micro-variant, while the rest of the alleles showed full concordance between the kits tested.

  • 9.
    Ansell, Ricky
    Linköping University, Department of Physics, Chemistry and Biology, Molecular genetics . Linköping University, The Institute of Technology.
    "Det var inte jag det var min bror" - Nära släkting och DNA-beviset2008In: Kriminalteknik, ISSN 1653-6169, no 3, 20-22 p.Article in journal (Other (popular science, discussion, etc.))
  • 10.
    Ansell, Ricky
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, Faculty of Science & Engineering. Nationellt forensiskt center, Linköping, Sverige.
    Dna-möte på NFC2015In: KriminalteknikArticle in journal (Other (popular science, discussion, etc.))
  • 11.
    Ansell, Ricky
    Linköping University, Department of Physics, Chemistry and Biology, Molecular genetics . Linköping University, The Institute of Technology.
    DNA-profiler och redovisning av resultatvärde2009In: Bevis, no 2, 9-11 p.Article in journal (Other (popular science, discussion, etc.))
  • 12.
    Ansell, Ricky
    Statens kriminaltekniska laboratorium, Linköping.
    Dna-spår betydelsefulla i sexualbrottsärenden2014In: Kriminalteknik, ISSN 1653-6169, no 3, 16-17 p.Article in journal (Other academic)
  • 13.
    Ansell, Ricky
    Nationellt forensiskt center - NFC, Linköping, Sverige.
    Forensisk dna-kongress i Krakow – ISFG 20152015In: Kriminalteknik, ISSN 1653-6169Article in journal (Other (popular science, discussion, etc.))
  • 14.
    Ansell, Ricky
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, The Institute of Technology. Statens kriminaltekniska laboratorium, SKL, Linköping.
    Forensiska uppslag - Spaningsinformation från SKL2012In: Kriminalteknik, ISSN 1653-6169, no 4, 12-13 p.Article in journal (Other (popular science, discussion, etc.))
  • 15.
    Ansell, Ricky
    Biologienheten SKL.
    Genetiska fantombiler2011In: Kriminalteknik, ISSN 1653-6169, no 1, 6-7 p.Article in journal (Other (popular science, discussion, etc.))
  • 16.
    Ansell, Ricky
    Linköping University, Department of Physics, Chemistry and Biology, Molecular genetics. Linköping University, The Institute of Technology.
    Hårfärg, ögonfärg och biogeografiskt ursprung2012In: Kriminalteknik, ISSN 1653-6169, no 2, 18-19 p.Article in journal (Other (popular science, discussion, etc.))
  • 17.
    Ansell, Ricky
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, The Institute of Technology. SKL, The Swedish National Laboratory of Forensic Science, Linköping, Sweden .
    Internal quality control in forensic DNA analysis2013In: Accreditation and Quality Assurance, ISSN 0949-1775, E-ISSN 1432-0517, Vol. 18, no 4, 279-289 p.Article in journal (Refereed)
    Abstract [en]

    The trail from initial evidence examination to a DNA profile reported to match a suspect is long and complex. The different nature and great variability in the biological and DNA evidence to be recovered and analyzed, add to this complexity. Internal quality controls play an important role in maintaining a high-quality performance in daily forensic biology and DNA profiling practice. In many cases are empirical rather than analytical approaches adopted. Obviously, despite the fact of being necessary, the internal quality controls performed still need to be kept rational at a limited, yet acceptable level. Quality control from a forensic biology and DNA profiling horizon has a wider context and does not only concern obvious fit-for-purpose verifications of analytical processes, chemicals, or reagents in daily routine practice. It also includes control on computerized laboratory management and expert systems, laboratory environmental DNA monitoring, and the use of elimination DNA databases. In addition, a structured recording and handling of non-conformances and “near failures” is essential. Proper management of the non-conformances supports continuous quality improvements by learning from the errors occurring in daily practice. High transparency of non-conformances is important not only for internal improvements, but also for the criminal justice system as well as to maintain public confidence and trust. Together the quality controls used aim at maintaining evidence and DNA sample integrity and to accomplish correct results and interpretations by verifying that methods used data transfers and interpretations made are correct and performed according to validated and accredited conditions.

  • 18.
    Ansell, Ricky
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, The Institute of Technology. Statens Kriminaltekniska Laboratorium (SKL), Linköping.
    Kvalitetsmöte med Forensic Science Regulator2014In: Kriminalteknik, ISSN 1653-6169, no 1, 22-23 p.Article in journal (Other academic)
  • 19.
    Ansell, Ricky
    Linköping University, Department of Physics, Chemistry and Biology, Molecular genetics . Linköping University, The Institute of Technology.
    Ny teknik för identifiering utan DNA2011In: Kriminalteknik, ISSN 1653-6169, no 3, 32- p.Article in journal (Other (popular science, discussion, etc.))
  • 20.
    Ansell, Ricky
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, The Institute of Technology. Statens kriminaltekniska laboratorium - SKL, Linköping.
    Nytt på dna-området2013Other (Other (popular science, discussion, etc.))
  • 21.
    Ansell, Ricky
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, The Institute of Technology.
    Pilotstudie om forensiska uppslag2014In: KriminalteknikArticle in journal (Other (popular science, discussion, etc.))
  • 22.
    Ansell, Ricky
    Linköping University, Department of Physics, Chemistry and Biology, Molecular genetics . Linköping University, The Institute of Technology.
    Sexualbrottsärenden på SKL2008In: Kriminalteknik, ISSN 1653-6169, no 4, 12-17 p.Article in journal (Other (popular science, discussion, etc.))
  • 23.
    Ansell, Ricky
    Linköping University, Department of Physics, Chemistry and Biology, Biology.
    Utveckling av arbetsmetoderna vid utredning av våldtäkter2014In: Kriminalteknik, Vol. 4, 10-11 p.Article in journal (Other (popular science, discussion, etc.))
  • 24.
    Ansell, Ricky
    et al.
    Swedish National Forensic Centre, Linköping, Sweden.
    Allen, Marie
    Molekylär patologi och rättsgenetik, Uppsala universitet.
    DNA-analyser inom brottsbekämpningen2016In: Skurk, sjuk eller släkt?: vem ska ha ditt DNA? / [ed] Eva Regårdh, Sofie Pehrssoon, Stockholm: Stiftelsen för strategisk forskning , 2016, 18-27 p.Chapter in book (Other academic)
    Abstract [sv]

    Idag räcker det med DNA från enstaka celler för att kunna få fram en DNA-profil som kan jämföras med per-soner eller andra DNA-spår. En DNA-träff mot ett biologiskt spår kan utgöra en mycket stark bevisning och vara avgörande för en fällande dom. DNA-teknik gör det möjligt att analysera och ta fram en DNA-profil för de allra flesta typer av humana biologiska spår som avsatts i samband med brott, såsom blod, sperma, vaginalsekret, saliv, hår och ”kontaktspår”. Teknikerna har med åren utvecklats och förfinats. På senare år har också det internationella utbytet av DNA-profiler ökat samtidigt som fortsatt teknik- och metodutveckling banar väg för fördjupade analy-ser som kan bidra till att klara upp brott. Det kan handla om att utifrån DNA-spår ringa in ungefärlig ålder, ursprung, hårfärg, ögonfärg och kroppsstorlek på en misstänkt gärningsman

  • 25.
    Ansell, Ricky
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Molecular genetics .
    Branicki, Wojciech
    Jagiellonian University, Kraków.
    The future of forensic human identification tools. Letter to the Editor.2009In: Problems of Forensic Sciences, ISSN 1230-7483, Vol. LXXX, 471-478 p.Article in journal (Other academic)
  • 26.
    Ansell, Ricky
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Molecular genetics . Linköping University, The Institute of Technology.
    Digréus, P.
    Swedish National Laboratory of Forensic Science (SKL), Linköping, Sweden.
    Andersson, A-C
    Swedish National Laboratory of Forensic Science (SKL), Linköping, Sweden.
    Nilsson, J.
    Swedish National Laboratory of Forensic Science (SKL), Linköping, Sweden.
    Dufva, C.
    Swedish National Laboratory of Forensic Science (SKL), Linköping, Sweden.
    Nordgaard, A.
    Swedish National Laboratory of Forensic Science (SKL), Linköping, Sweden.
    Contamination monitoring in the forensic DNA laboratory and a simple graphical model for unbiased EPG classification2011In: Book of Abstracts, 2011, 199- p.Conference paper (Refereed)
    Abstract [en]

    In this work we present a procedure for contamination monitoring in a trace search and recovery area and agraphical classification model. The recent launch of more sensitive and robust amplification kits increases thepossibility to detect minute amounts of trace DNA. As a consequence this enhances our need to establish eliminationdatabases and demands for an increased awareness on how to avoid contamination. DNA contaminatingthe evidence somewhere along the forensic process has the potential to destroy the evidence or totally confuseand mislead the crime investigation. In the forensic laboratory specific areas are designated for different partsof the process: trace search and recovery, pre-PCR, post-PCR etc. Work procedures and cleaning routines areadapted to minimise the risk of contamination. Monitoring presence of DNA in the laboratory environment, onspecific surfaces or instruments of interest, is one way to assess these risks and will in addition increase ourknowledge on how to improve cleaning routines and behaviour in the lab. A monitoring process needs to someextent be standardised in order to become unbiased and independent on an individual level, regarding bothwhere and how samples are taken and how the results are classified. The graphical model constitutes a lineartransformation of a three-dimensional “credit system” based on alleles, markers and peak heights, into a twodimensional classification. The standardisation allows results to be compared over time, and if applied to otherwork-areas comparison between different parts of the process will be possible.

  • 27.
    Ansell, Ricky
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, The Institute of Technology. Statens Kriminaltekniska Laboratorium (SKL), Linköping.
    Eriksson, Helena
    Statens Kriminaltekniska Laboratorium (SKL), Linköping.
    Centrum för genetisk identifiering2014In: Kriminalteknik, ISSN 1653-6169, no 1, 21- p.Article in journal (Other academic)
  • 28.
    Ansell, Ricky
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, The Institute of Technology. Statens Kriminaltekniska Laboratorium (SKL), Linköping.
    Hedman, Johannes
    Statens Kriminaltekniska Laboratorium (SKL), Linköping.
    Snabbanalysinstrumentet RapidHIT på SKL2014In: Kriminalteknik, ISSN 1653-6169, no 1, 18-19 p.Article in journal (Other academic)
    Abstract [sv]

     

  • 29.
    Ansell, Ricky
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Molecular genetics . Linköping University, The Institute of Technology.
    Heimer, G.
    Lucas, S.
    Ny, M.
    Rätt prover i vården kan fälla våldtäktsmän2009In: Abstract Symposium 26, 2009Conference paper (Refereed)
  • 30.
    Ansell, Ricky
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Molecular genetics .
    Lucas, Steven
    Heimer, Gun
    NCK och SKL lanserar "Spårsäkringssats efter sexuella övergrepp"2010In: Kriminalteknik, no 3/4, 6-7 p.Article in journal (Other (popular science, discussion, etc.))
  • 31.
    Ansell, Ricky
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Molecular genetics .
    Lucas, Steven
    Heimer, Gun
    Spårsäkringssats efter sexuella övergrepp2010In: BEVIS, no 4, 19-21- p.Article in journal (Other (popular science, discussion, etc.))
  • 32.
    Ansell, Ricky
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, Faculty of Science & Engineering. Polismyndigheten - Nationellt Forensiskt Centrum.
    Nordgaard, Anders
    Linköping University, Department of Computer and Information Science, Statistics. Linköping University, Faculty of Arts and Sciences. Polismyndigheten - Nationellt Forensiskt Centrum.
    Hedell, Ronny
    Polismyndigheten - Nationellt Forensiskt Centrum.
    Interpretation of DNA Evidence: Implications of Thresholds Used in the Forensic Laboratory2014Conference paper (Other academic)
    Abstract [en]

    Evaluation of forensic evidence is a process lined with decisions and balancing, not infrequently with a substantial deal of subjectivity. Already at the crime scene a lot of decisions have to be made about search strategies, the amount of evidence and traces recovered, later prioritised and sent further to the forensic laboratory etc. Within the laboratory there must be several criteria (often in terms of numbers) on how much and what parts of the material should be analysed. In addition there is often a restricted timeframe for delivery of a statement to the commissioner, which in reality might influence on the work done. The path of DNA evidence from the recovery of a trace at the crime scene to the interpretation and evaluation made in court involves several decisions based on cut-offs of different kinds. These include quality assurance thresholds like limits of detection and quantitation, but also less strictly defined thresholds like upper limits on prevalence of alleles not observed in DNA databases. In a verbal scale of conclusions there are lower limits on likelihood ratios for DNA evidence above which the evidence can be said to strongly support, very strongly support, etc. a proposition about the source of the evidence. Such thresholds may be arbitrarily chosen or based on logical reasoning with probabilities. However, likelihood ratios for DNA evidence depend strongly on the population of potential donors, and this may not be understood among the end-users of such a verbal scale. Even apparently strong DNA evidence against a suspect may be reported on each side of a threshold in the scale depending on whether a close relative is part of the donor population or not. In this presentation we review the use of thresholds and cut-offs in DNA analysis and interpretation and investigate the sensitivity of the final evaluation to how such rules are defined. In particular we show what are the effects of cut-offs when multiple propositions about alternative sources of a trace cannot be avoided, e.g. when there are close relatives to the suspect with high propensities to have left the trace. Moreover, we discuss the possibility of including costs (in terms of time or money) for a decision-theoretic approach in which expected values of information could be analysed.

  • 33.
    Ansell, Ricky
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Molecular genetics . Linköping University, The Institute of Technology.
    Olsén, E-L
    Swedish National Laboratory of Forensic Science (SKL), Linköping, Sweden.
    Eddenberger, E.
    Swedish National Laboratory of Forensic Science (SKL), Linköping, Sweden.
    Mattsson, M.
    Swedish National Laboratory of Forensic Science (SKL), Linköping, Sweden.
    Phadebas® Press test and the presence of amylases in different body fluids deposited on textile2011In: Book of Abstracts, 2011, 136- p.Conference paper (Refereed)
    Abstract [en]

    In forensic DNA casework saliva stains with epithelial cells can be very useful even presenting the key evidence.Tests for amylase activity, like Phadebas® Press test, help locate stains and indicate presence of saliva. Sensitivityis high, with positive amylase tests obtained prior to detectable levels of DNA and saliva diluted to 1:100readily generate a positive reaction with Phadebas® Press test for presence of amylase. The salivary amylaseactivity varies on individual basis over time as well as it does between individuals. In addition some individualssecrete high levels of amylases [1,2]. However, amylases are present in other body fluids as well, generally toomuch lower levels than saliva. Due to sensitivity of amylase tests there is a potential interference by otherfluids when using them to verify the presence of saliva. Other studies also demonstrate that e.g. faeces can givepositive reactions.For underwear the presence of several different body fluids might have natural causes, including vaginal secretions,(menstrual) blood, urine, faeces, as well as semen and saliva. Here we present the use of Phadebas® Presstest on underwear with naturally deposited body fluids and single source body fluid mock samples including oneindividual with higher levels of amylase activity. Our results and implications are discussed.

    [1] J. Hedman, E. Dalin, B. Rasmusson, R. Ansell (2011). Forensic Science International; Genetics, 5, 194–198.

    [2] J. Hedman, K. Gustavsson, R. Ansell (2008). Forensic Science International; Genetics Supplement Series, 1(1), 430–432.

  • 34.
    Ansell, Ricky
    et al.
    National Laboratory of Forensic Science (SKL), Linköping, Sweden.
    Rasmusson, Birgitta
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    A Swedish PerspectiveThe Forensic Use of Bioinformation: Ethical Issues: Nuffield Council on Bioethics2008In: BioSocieties, ISSN 1745-8552, E-ISSN 1745-8560, Vol. 3, no 1, 88-92 p.Article in journal (Other academic)
    Abstract [en]

    The Nuffield Report is well-written, clear, extensive and up to date, and it covers most of the major ethical issues in the field of forensic DNA analysis and database searching. The ethical analysis is thorough and based on solid theoretical ground.

  • 35.
    Ansell, Ricky
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Molecular genetics. Linköping University, Faculty of Health Sciences.
    Stegeryd, Y.
    Läkares säkring av bevis efter sexualbrott viktig del i rättsprocessen2008In: Läkartidningen, ISSN 0023-7205, Vol. 105, no 9, 634-637 p.Article in journal (Refereed)
    Abstract [sv]

    In cases of sexual assault, physical evidence can be of crucial importance for a conviction. Intimate samples initially collected by a physician can prove to be the only supporting evidence for the prosecution to present at court proceedings. New analysis techniques and methods have increased the positive outcome of the samples collected. This in combination with increased use of national criminal DNA databases results in the solving of sexual crimes with unknown perpetrators. The use of standardised rape care kits facilitates the work of the physician in performing an adequate sampling procedure. The Swedish "rape care kit" has been developed and updated in response to experience gained and new possibilities.

  • 36.
    Ansell, Ricky
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, The Institute of Technology. Statens kriminaltekniska laboratorium, SKL, Linköping.
    Stegeryd, Yvonne
    Statens kriminaltekniska laboratorium, SKL, Linköping.
    Hallingström, Marie-Louise
    Rättsmedicinalverket, RMV, Linköping.
    Spårsäkringssats efter sexuella övergrepp anpassas till PUST2013In: Kriminalteknik, ISSN 1653-6169, 20-21 p.Article in journal (Other (popular science, discussion, etc.))
  • 37.
    Ansell, Ricky
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Molecular genetics .
    Sundberg, Liselotte
    Forensiska uppslag - ett kommande verksamhetsområde vid SKL2010In: Kriminalteknik, no 3/4, 4-5 p.Article in journal (Other (popular science, discussion, etc.))
  • 38.
    Ansell, Ricky
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, The Institute of Technology.
    Widén, Christina
    Statens kriminaltekniska laboratorium.
    Ny lagstiftning för DNA elimineringsbas i Sverige2014In: Kriminalteknik, Vol. 4, 28-30 p.Article in journal (Other (popular science, discussion, etc.))
  • 39.
    Ansell, Ricky
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, Faculty of Science & Engineering. Swedish National Forensic Centre, Linköping, Sweden.
    Widén, Christina
    Biology Unit, Swedish National Forensic Centre (NFC), Link€oping, Sweden.
    Swedish Legislation Regarding Forensic DNA Elimination Databases2016In: Forensic Science Policy & Management: An International Journal , ISSN 1940-9044, Vol. 7, no 1-2, 20-36 p.Article in journal (Refereed)
    Abstract [en]

    Evidence contaminated with DNA from staff, police, and other individuals can have a dramaticimpact on an investigation and can mislead police inquiries. Forensic DNA elimination databases(EDB) are used to minimize the risks associated with DNA contamination. Central issues withmaintaining such databases include the basis for sample collection, sample, and profile integrity, aswell as retention times, database access, and procedures when a database match occurs. Followingyears of discussion, debate, and the use of an “in house” EDB at the Swedish National ForensicCentre (NFC), these issues have now been resolved by passing legislation on DNA EDB. According tothe legislation, sampling for EDB purposes is mandatory for certain forensic professionals, as well asfor other individuals who need access to the premises handling DNA evidence. In the event of adatabase match, the match can only be reviewed and evaluated for quality purposes and the nameof the donor cannot be disclosed to the crime inquiry. Thus, as a consequence, if a contaminationevent is not the probable cause the legal limitation opens for impunity for individuals included inthe database.KEYWORDSContamination; DNA;elimination database;forensic science; legislationIntroduction

  • 40.
    Benschop, Corina C G
    et al.
    Division of Biological Traces, Netherlands Forensic Institute.
    Connolly, Edward
    Forensic Science Ireland.
    Ansell, Ricky
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, Faculty of Science & Engineering. Swedish National Forensic Centre, Linköping, Sweden.
    Kokshoorn, Bas
    Division of Biological Traces, Netherlands Forensic Institute.
    Results of an inter and intra laboratory exercise on the assessment of complex autosomal DNA profiles.2017In: Science & justice, ISSN 1355-0306, E-ISSN 1876-4452, Vol. 57, no 1, 21-27 p.Article in journal (Refereed)
    Abstract [en]

    The interpretation of complex DNA profiles may differ between laboratories and reporting officers, which can lead to discrepancies in the final reports. In this study, we assessed the intra and inter laboratory variation in DNA mixture interpretation for three European ISO17025-accredited laboratories. To this aim, 26 reporting officers analyzed five sets of DNA profiles. Three main aspects were considered: 1) whether the mixed DNA profiles met the criteria for comparison to a reference profile, 2) the actual result of the comparison between references and DNA profiling data and 3) whether the weight of the DNA evidence could be assessed. Similarity in answers depended mostly on the complexity of the tasks. This study showed less variation within laboratories than between laboratories which could be the result of differences between internal laboratory guidelines and methods and tools available. Results show the profile types for which the three laboratories report differently, which informs indirectly on the complexity threshold the laboratories employ. Largest differences between laboratories were caused by the methods available to assess the weight of the DNA evidence. This exercise aids in training forensic scientists, refining laboratory guidelines and explaining differences between laboratories in court. Undertaking more collaborative exercises in future may stimulate dialog and consensus regarding interpretation. For training purposes, DNA profiles of the mixed stains and questioned references are made available.

  • 41.
    Chaitanya, Lakshmi
    et al.
    Erasmus MC University Medical Centre Rotterdam, The Netherlands.
    Walsh, Susan
    Erasmus MC University Medical Centre Rotterdam, The Netherlands.
    Dyrberg Andersen, Jeppe
    University of Copenhagen, Denmark.
    Ansell, Ricky
    Swedish National Laboratory of Forensic Science (SKL), Linköping, Sweden.
    Ballantyne, Kaye
    Forensic Services Department, Victoria Police, Macleod, Victoria, Australia.
    Ballard, David
    School of Biomedical Sciences, King's College London, UK.
    Banemann, Regine
    Kriminaltechnik, Bundeskriminalamt, Wiesbaden, Germany.
    Maria Bauer, Christiane
    Innsbruck Medical University, Austria.
    Margarida Bento, Ana
    Instituto Nacional de Medicina Legal, Coimbra, Portugal.
    Brisighelli, Francesca
    Università Cattolica del Sacro Cuore, Rome, Italy.
    Capal, Tomas
    Institute of Criminalistics, Prague, Czech Republic.
    Clarisse, Lindy
    Netherlands Forensic Institute, The Hague, The Netherlands.
    Gross, Theresa E.
    University of Cologne, Germany.
    Haas, Cordula
    University of Zurich, Switzerland.
    Hoff-Olsen, Per
    Norwegian Institute of Public Health, Oslo, Norway.
    Hollard, Clémence
    Université de Strasbourg, Institut de Médecine Légale, France.
    Keyser, Christine
    Université de Strasbourg, Institut de Médecine Légale, France.
    Kiesler, Kevin M.
    National Institute of Standards and Technology, Gaithersburg, MD, USA.
    Kohler, Priscila
    Norwegian Institute of Public Health, Oslo, Norway.
    Kupiec, Tomasz
    Institute of Forensic Research, Kraków, Poland.
    Linacre, Adrian
    Flinders University, Adelaide, South Australia, Australia.
    Minawi, Anglika
    Kriminaltechnik, Bundeskriminalamt, Wiesbaden, Germany.
    Morling, Niels
    University of Copenhagen, Denmark.
    Nilsson, Helena
    National Board of Forensic Medicine, Linköping, Sweden.
    Norén, Lina
    Swedish National Laboratory of Forensic Science (SKL), Linköping, Sweden.
    Ottens, Renée
    Flinders University, Adelaide, South Australia, Australia.
    Palo, Jukka U.
    University of Helsinki, Finland.
    Parson, Walther
    Innsbruck Medical University, Austria.
    Pascali, Vincenzo L.
    Università Cattolica del Sacro Cuore, Rome, Italy.
    Philips, Chris
    University of Santiago de Compostela, Spain.
    João Porto, Maria
    Instituto Nacional de Medicina Legal, Coimbra, Portugal.
    Sajantila, Antti
    University of Helsinki, Finland.
    Schneider, Peter M.
    University of Cologne, Germany.
    Sijen, Titia
    Netherlands Forensic Institute, The Hague, The Netherlands.
    Söchtig, Jens
    University of Santiago de Compostela, Spain.
    Syndercombe-Court, Denise
    School of Biomedical Sciences, King's College London, UK.
    Tillmar, Andreas
    National Board of Forensic Medicine, Linköping, Sweden.
    Turanska, Martina
    Institute of Forensic Science, Slovenská Lupca, Slovakia.
    Vallone, Peter M.
    National Institute of Standards and Technology, Gaithersburg, MD, USA.
    Zatkalíková, Lívia
    Institute of Forensic Science, Slovenská Lupca, Slovakia.
    Zidkova, Anastassiya
    Charles University in Prague and General University Hospital in Prague, Czech Republic.
    Branicki, Wojciech
    Institute of Forensic Research, Kraków, Poland.
    Kayser, Manfred
    Erasmus MC University Medical Centre Rotterdam, The Netherlands.
    Collaborative EDNAP exercise on the IrisPlex system for DNA based prediction of human eye colour2014In: Forensic Science International: Genetics, ISSN 1872-4973, E-ISSN 1878-0326, Vol. 11, 241-251 p.Article in journal (Refereed)
    Abstract [en]

    The IrisPlex system is a DNA-based test system for the prediction of human eye colour from biological samples and consists of a single forensically validated multiplex genotyping assay together with a statistical prediction model that is based on genotypes and phenotypes from thousands of individuals. IrisPlex predicts blue and brown human eye colour with, on average, >94% precision accuracy using six of the currently most eye colour informative single nucleotide polymorphisms (HERC2 rs12913832, OCA2 rs1800407, SLC24A4 rs12896399, SLC45A2 (MATP) rs16891982, TYR rs1393350, and IRF4 rs12203592) according to a previous study, while the accuracy in predicting non-blue and non-brown eye colours is considerably lower. In an effort to vigorously assess the IrisPlex system at the international level, testing was performed by 21 laboratories in the context of a collaborative exercise divided into three tasks and organised by the European DNA Profiling (EDNAP) Group of the International Society of Forensic Genetics (ISFG). Task 1 involved the assessment of 10 blood and saliva samples provided on FTA cards by the organising laboratory together with eye colour phenotypes; 99.4% of the genotypes were correctly reported and 99% of the eye colour phenotypes were correctly predicted. Task 2 involved the assessment of 5 DNA samples extracted by the host laboratory from simulated casework samples, artificially degraded, and provided to the participants in varying DNA concentrations. For this task, 98.7% of the genotypes were correctly determined and 96.2% of eye colour phenotypes were correctly inferred. For Tasks 1 and 2 together, 99.2% (1875) of the 1890 genotypes were correctly generated and of the 15 (0.8%) incorrect genotype calls, only 2 (0.1%) resulted in incorrect eye colour phenotypes. The voluntary Task 3 involved participants choosing their own test subjects for IrisPlex genotyping and eye colour phenotype inference, while eye photographs were provided to the organising laboratory and judged; 96% of the eye colour phenotypes were inferred correctly across 100 samples and 19 laboratories. The high success rates in genotyping and eye colour phenotyping clearly demonstrate the reproducibility and the robustness of the IrisPlex assay as well as the accuracy of the IrisPlex model to predict blue and brown eye colour from DNA. Additionally, this study demonstrates the ease with which the IrisPlex system is implementable and applicable across forensic laboratories around the world with varying pre-existing experiences.

  • 42.
    Digréus, P.
    et al.
    Swedish National Laboratory of Forensic Science, Linköping.
    Andersson, A-C.
    Swedish National Laboratory of Forensic Science, Linköping.
    Nordgaard, A.
    Swedish National Laboratory of Forensic Science, Linköping.
    Ansell, Ricky
    Linköping University, Department of Physics, Chemistry and Biology, Molecular genetics . Linköping University, The Institute of Technology.
    Contamination monitoring in the forensic DNA laboratory and a simple graphical model for unbiased EPG classification2011In: Forensic Science International: Genetics, Supplement Series, ISSN 1875-1768, Vol. 3, no 1, e299-e300 p.Article in journal (Refereed)
    Abstract [en]

    Monitoring presence and level of background DNA in forensic DNA laboratory environments can be used to control work routines and cleaning procedures and to follow changes in these, as well as being an indicator for increased/decreased contamination risk. Previous monitoring routines as sampling and interpretation have not been standardised, making it difficult to compare between different sampling events and observe potential trends. Factor analysis was used to generate a simple graphical classification model for unbiased ranking of electropherograms, which can be modified according to user's need, taking into account number of detected alleles, markers and peak height.

  • 43.
    Foreberg, C.
    et al.
    Swedish National Forensic Centre, Linköping, Sweden.
    Wallmark, N.
    Swedish National Forensic Centre, Linköping, Sweden.
    Hedell, R.
    Swedish National Forensic Centre, Linköping, Sweden; Department of Mathematical Sciences, Chalmers University of Technology and University of Gothenburg, Gothenburg, Sweden.
    Jansson, L.
    Applied Microbiology, Lund University, Lund, Sweden.
    Ansell, Ricky
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, Faculty of Science & Engineering. Swedish National Forensic Centre, Linköping, Sweden.
    Hedman, J.
    Swedish National Forensic Centre, Linköping, Sweden; Applied Microbiology, Lund University, Lund, Sweden.
    Reference material for comparison of different adhesive tapes for forensic DNA sampling2015In: Forensic Science International: Genetics Supplement Series, ISSN 1875-1768, E-ISSN 1875-175X, Vol. 5, e454-e455 p.Article in journal (Refereed)
    Abstract [en]

    Tape-lifting is an efficient method for collecting traces of cellular material from fabrics. Since 2006, an in-house adhesive tape has been used in casework at the Swedish National Forensic Centre, Linköping. Although this tape gives good DNA yields, we aim to replace it with a commercial tape to save cost and labour. In order to enable a fair comparison between different adhesive tapes, we have developed and evaluated a method for production of relevant reference material. One person, known to be a good shedder, wore identical long-sleeved T-shirts under controlled circumstances, and trace recovery was systematically performed with the in-house tape (3 T-shirts, total of 24 samples). Each sample was DNA extracted and quantified to find the normal variation within the reference material. The DNA recovery differed considerably between samples, with DNA concentrations between 0.010–0.48 ng/μL (mean: 0.083, SD: 0.12 ng/μL). Applying such a reference material for comparison between two commercial tapes and our in-house tape resulted in mean DNA recoveries plus/minus one standard deviation of 0.013 ± 0.006 ng/μL (Scenesafe FAST Box), 0.012 ± 0.007 ng/μL (Touch tape), and 0.023 ± 0.013 ng/μL (in-house tape). The in-house tape gave statistically significant higher yield compared to Touch tape (p  < 0.05), but for Scenesafe FAST Box the difference was not significant. The shedding of cells to clothes cannot be fully controlled. Having a systematically prepared, casework-like reference material with known variation is therefore vital for comparative studies of tapes

  • 44.
    Foreberg, Christina
    et al.
    Swedish National Forensic Centre, Linköping, Sweden.
    Jansson, Linda
    Applied Microbiology, Department of Chemistry, Lund University, Lund, Sweden.
    Ansell, Ricky
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, Faculty of Science & Engineering. Swedish National Forensic Centre, Linköping, Sweden.
    Hedman, Johannes
    Swedish National Forensic Centre, Linköping, Sweden, Applied Microbiology, Department of Chemistry, Lund University, Lund, Sweden.
    High-throughput DNA extraction of forensic adhesive tapes2016In: Forensic Science International: Genetics, ISSN 1872-4973, E-ISSN 1878-0326, Vol. 24, 158-163 p.Article in journal (Refereed)
    Abstract [en]

    Tape-lifting has since its introduction in the early 2000's become a well-established sampling method in forensic DNA analysis. Sampling is quick and straightforward while the following DNA extraction is more challenging due to the "stickiness", rigidity and size of the tape. We have developed, validated and implemented a simple and efficient direct lysis DNA extraction protocol for adhesive tapes that requires limited manual labour. The method uses Chelex beads and is applied with SceneSafe FAST tape. This direct lysis protocol provided higher mean DNA yields than PrepFiler Express BTA on Automate Express, although the differences were not significant when using clothes worn in a controlled fashion as reference material (p=0.13 and p=0.34 for T-shirts and button-down shirts, respectively). Through in-house validation we show that the method is fit-for-purpose for application in casework, as it provides high DNA yields and amplifiability, as well as good reproducibility and DNA extract stability. After implementation in casework, the proportion of extracts with DNA concentrations above 0.01ng/μL increased from 71% to 76%. Apart from providing higher DNA yields compared with the previous method, the introduction of the developed direct lysis protocol also reduced the amount of manual labour by half and doubled the potential throughput for tapes at the laboratory. Generally, simplified manual protocols can serve as a cost-effective alternative to sophisticated automation solutions when the aim is to enable high-throughput DNA extraction of complex crime scene samples.

  • 45. Forsberg, C.
    et al.
    Wallmark, N.
    Hedell, R.
    Jansson, L.
    Ansell, Ricky
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, Faculty of Science & Engineering.
    Hedman, J.
    Reference material for comparison of different adhesive tapes for forensic DNA sampling: -2015In: Abstracts ISFG, 2015, 267-268 p.Conference paper (Refereed)
    Abstract [en]

    Tape-lifting is an efficient method for collecting traces of cellular material from fabrics. Since 2006, an in-house adhesive tape has been used in casework at the Swedish National Forensic Centre, Linköping. Although this tape gives good DNA yields, we aim to replace it with a commercial tape to save cost and labor. In order to enable a fair comparison between different adhesive tapes, we have developed and evaluated a method for production of relevant reference material. One person, known to be a good shedder, wore identical long-sleeved T-shirts under controlled circumstances, and trace recovery was systematically performed with the in-house tape (3 T-shirts, total of 24 samples). Each sample was DNA extracted (Chelex) and quantified (Quantifiler Human DNA Quantification kit) to find the normal variation within the reference material.

    The DNA recovery differed considerably between samples, with obtained DNA concentrations between 0.010-0.481 ng/μL (mean: 0.083, standard deviation: 0.116 ng/μL). Applying such a reference material for comparison between two commercial tapes and our in-house tape resulted in mean DNA recoveries plus/ minus one standard deviation of 0.013±0.006 ng/μL (Scenesafe FAST Box), 0.012±0.007 ng/μL (Touch Tape), and 0.023±0.013 ng/μL (in-house tape).

    The in-house tape gave statistically significant higher yield compared to Touch Tape (p<0.05), but for Scenesafe the difference was not significant. Shedding of cells to worn clothes is a random process. Having a systematically prepared, casework-like reference material with known variation is therefore vital for comparative studies of tapes.

  • 46. Gunnarsson, Johan
    et al.
    Helena, Eriksson
    Ansell, Ricky
    Linköping University, Department of Physics, Chemistry and Biology, Molecular genetics . Linköping University, The Institute of Technology.
    Success rates of a forensic tape-lift method for DNA recovery2010In: Problems of Forensic Sciences, ISSN 1230-7483, Vol. LXXXIII, 243-254 p.Article in journal (Refereed)
  • 47. Hedberg, K.
    et al.
    Ansell, Ricky
    Linköping University, Department of Physics, Chemistry and Biology, Molecular genetics. Linköping University, The Institute of Technology.
    Omtopsning av misstänkta? PMF ger besked!2011In: Kriminalteknik, ISSN 1653-6169, no 4, 4-5 p.Article in journal (Other academic)
  • 48.
    Hedell, R.
    et al.
    Swedish National Laboratory of Forensic Science, Linköping.
    Nordgaard, A.
    Swedish National Laboratory of Forensic Science, Linköping.
    Ansell, Ricky
    Linköping University, Department of Physics, Chemistry and Biology, Molecular genetics . Linköping University, The Institute of Technology.
    Discrepancies between forensic DNA databases2011In: Forensic Science International: Genetics, Supplement Series, ISSN 1875-1768, Vol. 3, no 1, e135-e136 p.Article in journal (Refereed)
    Abstract [en]

    In this study we present a comprehensive statistical comparison between a number of reference databases used in Sweden and two databases of DNA profiles from casework. Our results show no substantial differences with respect to various measurements of overall discrepancies but reveal significant differences for individual alleles at several loci.

  • 49.
    Hedell, Ronny
    et al.
    Statens kriminaltekniska laboratorium (SKL).
    Ansell, Ricky
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, The Institute of Technology. Statens kriminaltekniska laboratorium (SKL), Linköping .
    Nära släktskap och dna-beviset; ”Om man bortser från möjligheten att det kommer från en nära släkting”2014In: Nättidningen Kriminalteknik.nuArticle in journal (Other (popular science, discussion, etc.))
    Abstract [sv]

    Sannolikheten för att helsyskon skulle uppvisa överensstämmande dna-profiler är låg för fullständiga eller nästan fullständiga profiler, speciellt med tanke på att det är ett mycket begränsat antal individer som kan ha denna släktskapsrelation.

    Uppstår det frågor i utredningen om nära släktskap kommer en jämförelse med berörd släkting att ge klargörande besked. Om en sådan direktjämförelse inte går att utföra kan en statistisk beräkning göras, alternativt går det att använda sig av en generell riskbedömning baserad på angiven släktskapsrelation. Vid en generell bedömning är valet av aktuell referenspopulation inte det primära.

    De högsta sannolikheterna för överensstämmande dna-profiler, både för obesläktade och nära släktingar, fås vid partiella dna-resultat med resultat i endast ett fåtal markörer och vid blandbildsresultat.

    Effekter på grund av valet av referenspopulation som beräkningsunderlag kan uppstå främst när det gäller ofullständiga dna-resultat. Används svensk referenspopulation i dessa fall ger det en fingervisning av sannolikheten för överensstämmelse.

    Uppfattningen om huruvida dna:t kan ha avsatts av en nära släkting till den tilltalade påverkas också av övriga relevanta fakta eller omständigheter i utredningen.

  • 50.
    Hedell, Ronny
    et al.
    Swedish National Laboratory of Forensic Science (SKL), Linköping, Sweden; Chalmers University of Technology and University of Gothenburg, Sweden .
    Dufva, Charlotte
    Swedish National Laboratory of Forensic Science (SKL), Linköping, Sweden .
    Ansell, Ricky
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, The Institute of Technology. Swedish National Laboratory of Forensic Science (SKL), Linköping, Sweden .
    Mostad, Petter
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology. Chalmers University of Technology and University of Gothenburg, Sweden.
    Hedman, Johannes
    Swedish National Laboratory of Forensic Science (SKL), Linköping, Sweden; Lund University, Sweden .
    Enhanced low-template DNA analysis conditions and investigation of allele dropout patterns2015In: Forensic Science International: Genetics, ISSN 1872-4973, E-ISSN 1878-0326, Vol. 14, 61-75 p.Article in journal (Refereed)
    Abstract [en]

    Forensic DNA analysis applying PCR enables profiling of minute biological samples. Enhanced analysis conditions can be applied to further push the limit of detection, coming with the risk of visualising artefacts and allele imbalances. We have evaluated the consecutive increase of PCR cycles from 30 to 35 to investigate the limitations of low-template (LT) DNA analysis, applying the short tandem repeat (STR) analysis kit PowerPlex ESX 16. Mock crime scene DNA extracts of four different quantities (from around 8–84 pg) were tested. All PCR products were analysed using 5, 10 and 20 capillary electrophoresis (CE) injection seconds. Bayesian models describing allele dropout patterns, allele peak heights and heterozygote balance were developed to assess the overall improvements in EPG quality with altered PCR/CE settings. The models were also used to evaluate the impact of amplicon length, STR marker and fluorescent label on the risk for allele dropout.

    The allele dropout probability decreased for each PCR cycle increment from 30 to 33 PCR cycles. Irrespective of DNA amount, the dropout probability was not affected by further increasing the number of PCR cycles. For the 42 and 84 pg samples, mainly complete DNA profiles were generated applying 32 PCR cycles. For the 8 and 17 pg samples, the allele dropouts decreased from 100% using 30 cycles to about 75% and 20%, respectively. The results for 33, 34 and 35 PCR cycles indicated that heterozygote balance and stutter ratio were mainly affected by DNA amount, and not directly by PCR cycle number and CE injection settings. We found 32 and 33 PCR cycles with 10 CE injection seconds to be optimal, as 34 and 35 PCR cycles did not improve allele detection and also included CE saturation problems.

    We find allele dropout probability differences between several STR markers. Markers labelled with the fluorescent dyes CXR-ET (red in electropherogram) and TMR-ET (shown as black) generally have higher dropout risks compared with those labelled with JOE (green) and fluorescein (blue). Overall, the marker D10S1248 has the lowest allele dropout probability and D8S1179 the highest. The marker effect is mainly pronounced for 30–32 PCR cycles. Such effects would not be expected if the amplification efficiencies were identical for all markers. Understanding allele dropout risks and the variability in peak heights and balances is important for correct interpretation of forensic DNA profiles.

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