The utility of whole genome amplification in forensic DNA analysis

Forensic biologists are often confronted with issues of limited DNA which may restrict their ability to generate an identification profile and reserve sample for future analysis. Although PCR is commonly used to amplify specific segments of DNA, whole genome amplification (WGA) is a process which is capable of replicating an entire sample; reducing the likelihood of entirely consuming evidence. WGA of low quantity clinical samples has been studied thoroughly, but there is nothing in the literature describing its use in forensic biology. The objective of this project was to characterize Improved Primer Extension Preamplification (I-PEP) and Multiple Displacement Amplification (MDA), two methods of WGA, on samples commonly seen in forensic laboratories by testing both low quality and quantity DNA. Control DNA, artificially degraded DNA, and DNA from fresh and aged blood, hair, and bone before and after WGA were PCR amplified to test maximum amplicon lengths and to examine product yields. No difference was seen in the maximum PCR product length of DNA from fresh blood, longer product was generated from aged blood, and there was a reduction in amplicon length from hair and aged bone after WGA. Product yield was increased 20 to 2000 fold by I-PEP and 1000 to 10,000 fold by MDA. All MDA tests on low quality samples were unsuccessful and often resulted in extensive non-target DNA amplification. Overall, I-PEP and MDA increased the product yield of high quality DNA, but they were not successful on highly degraded samples.