The influence of hand dominance, hand washing and sampling technique on quantity of DNA recovered from handled plastic tubes

Abstract

There are several previously published studies suggesting that different people deposit different quantities of their own DNA on items they handled, so can be considered good or bad shedders. This study aimed to investigate the amount of DNA deposited on sterile plastic tubes handled by the employees in our lab for 15 seconds. In particular, we wanted to test if there are differences in the amount of DNA deposited by dominant versus non-dominant hand. Moreover, we investigated the amount of DNA deposited before, immediately after and 30 minutes after hand washing. In the end, this study compared two sampling techniques, namely wet and dry swabbing, aiming to define the technique that guarantees better recovery of touch DNA. A samples were collected from 6 individuals and analyzed for differences in DNA quantity between the two hands of the same individual, but also between different individuals and different sampling techniques. In general, our preliminary results have shown that there are no significant differences between dominant vs nondominant hand. Consistent differences were observed between individuals regarding their ability to deposit biological material on handled objects. Sampling technique was factor that significantly influenced the amount of recovered DNA, suggesting that wet swabbing recovered higher DNA amounts compared to dry swabbing. Hand washing can be considered efficient anti contaminant measure as it significantly reduces the amount of biological material deposited on handled object. Further studies are needed to confirm our findings, especially those considering quantification of DNA deposited by individuals for prolonged period of time.

Keywords

• shedder status
• hand washing
• dna amount
• forensics