Verification of alleles by using peak height thresholds and quality control of STR profiling kits
2011 (English)In: Forensic Science International: Genetics, Supplement Series, ISSN 1875-1768, Vol. 3, no 1, e251-e252 p.Article in journal (Refereed) Published
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.
Place, publisher, year, edition, pages
Elsevier, 2011. Vol. 3, no 1, e251-e252 p.
STR; Peak height thresholds; DNA profiling kits; Heterozygote balance; Signal repeatability; Inhibitor tolerance
IdentifiersURN: urn:nbn:se:liu:diva-72737DOI: 10.1016/j.fsigss.2011.09.003OAI: oai:DiVA.org:liu-72737DiVA: diva2:461921