A comparison of methods for forensic DNA extraction: Chelex-100® and the QIAGEN DNA Investigator Kit (manual and automated)

Efficient isolation of DNA from a sample is the basis for successful forensic DNA profiling. There are many DNA extraction methods available and they vary in their ability to efficiently extract the DNA; as well as in processing time, operator intervention, contamination risk and ease of use. In recent years, automated robots have been made available which speed up processing time and decrease the amount of operator input. This project was set up to investigate the efficiency of three DNA extraction methods, two manual (Chelex®-100 and the QIAGEN DNA Investigator Kit) and one automated (QIAcube), using both buccal cells and blood stains as the DNA source. Extracted DNA was quantified using real-time PCR in order to assess the amount of DNA present in each sample. Selected samples were then amplified using AmpFlSTR SGM Plus amplification kit. The results suggested that there was no statistical difference between results gained for the different methods investigated, but the automated QIAcube robot made sample processing much simpler and quicker without introducing DNA contamination.