Comparative Study of Touch Dna Recovery from Metals

Abstract

Touch DNA requires a special collection approach to recover the minute amounts of DNA left behind in skin cells. Touch DNA has been successfully recovered from surfaces such as fabric, plastic and wood. However, a consistent effective method to recover sufficient DNA for profiling from metals has yet to be developed. This study investigated in depth the collection of low amounts of DNA deposited on six different types of metal surfaces using five different types of collection tools in combination with four different types of buffer solutions to determine the method that yields the greatest and most consistent recovery of DNA. For all collection procedures, the DNA IQ DNA extraction kit was used to extract and recover DNA collected with the difference swab/solvent combinations. Statistical analysis was completed using ANOVA with Tukey�s multiple comparison test.Sarkosyl buffer combined with tape lift to recover DNA left behind on brass-plated metals showed the highest mean recovery of DNA spotted and dried onto the metal. However the same combination of Sarkosyl buffer and tape lift did not perform similarly across all six metals. This study showed that not only do buffer solution and collection tool play a role in the recovery of touch DNA, but the type of metal the DNA is deposited on also plays a significant role in the recovery rate of touch DNA left behind on metals.