Mixed DNA profiles from single-donors
2015 (English)In: Abstract book, 7th European Academy of Forensic Science, EAFS, Prag, Tjeckien, 2015, 2015, 538- p.Conference paper, Abstract (Other academic)
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.
Place, publisher, year, edition, pages
2015. 538- p.
IdentifiersURN: urn:nbn:se:liu:diva-121347OAI: oai:DiVA.org:liu-121347DiVA: diva2:853689
7th European Academy of Forensic Science, EAFS 2015, Prague, Czech Republic, 6-11 September 2015