mRNA profiling technique: application to an old casework

We report on a homicide where the victim died from numerous stab wounds, after a prolonged struggle in which a large amount of blood had been spattered. The victim was married and so authorities questioned her husband that became the suspect. Police inspected the house of the suspect’s mother finding a white sweater inside a washbasin located in the laundry. Sweater corresponded to the one worn by the suspect. No bloodstains were found during the examination. When luminol was applied, three areas of luminescence developed. In order to confirm the presence of human blood, traces were sampled and tested using HemDirect Hemoglobin test (SERATEC®). All samples were negative. Genetic analysis, accomplished with AmpFlSTR® NGM™ amplification kit (Thermo Scientific®), revealed the presence of the victim’s genetic profile. Due to the lack of this essential data, fortunately, it has been possible to convict the suspect only by other evidence collected by investigators. Relating to an emerging technique that showed remarkable progresses in body fluids identification [1], samples were re-analyzed applying mRNA profiling. A DNA/RNA co-extraction was performed using AllPrep DNA/RNA Mini Kit (QIAGEN®). For the reverse transcription reaction, random primers and RETROscript (Ambion®) were used. Samples were amplified using Multiplex PCR Mastermix (Qiagen®) according to the manufacturer's instructions. Primer sequences were adopted from Ven den Berge et al. [2]. DNA was STR typed using AmpFlSTR® NGM™ kit (Thermo Scientific®). Capillary electrophoresis was run on an ABI PRISM 310 Genetic Analyzer (Thermo Scientific®). Results showed all samples positive for mRNA markers used. The genetic profile from the samples was the same previously achieved.