Persistence and secondary transfer of DNA from previous users of equipment

Abstract A study of persistence of DNA from previous users' computer equipment and secondary transfer to a new user's hand was conducted. Four individuals (two male and two female) swapped their personal computer keyboard and mouse. Samples were collected from parts of the equipment (background DNA), and from the new users' hands on the first day and then frequently until the previous users' DNA could not be detected. Additional Y-analysis was performed on the samples collected from the female participants' hands. In the samples collected from the new users' hands on the first day of the swap, alleles identical to those of the previous user were observed in mixtures in all cases except the samples collected from the good shedder's hands. This study shows that it is possible to transfer an initial user's DNA from the computer equipment to the hands of a new user up to eight days after receiving the equipment.