Recovery of DNA from Shoes

Abstract

ABSTRACTShoes left at scenes of crime have historically been used as forensic links between suspect and scene, utilizing barefoot morphology. With the increased sensitivity of deoxyribonucleic acid (DNA) analysis, the question arises as to whether DNA profiles linking suspects to shoes left at scenes could replace barefoot morphology, or be used as corroborative evidence. Two studies were run in order to ascertain if the wearer of the shoe could be determined consistently. Three areas of a shoe were swabbed: the heel, the lace/tongue, and the insole. Twenty-one shoes were analysed in Study 1 and forty-three shoes were analysed in Study 2. The results of these studies indicate that DNA can be profiled in some instances, but not from every shoe. Environmental factors and the wearer's ability to slough skin cells determined if DNA was found in the shoe or not. The lace/tongue region of the shoe provides more information concerning the wearer than the other areas swabbed. This may be due to the fact that the lace/tongue region of a shoe is the main area of contact with the wearer's hand and the shoe. It should also be noted that on many of the shoes where DNA was found, the resulting profile was of mixed origin or could be attributed to multiple persons. This suggests that besides the wearer's DNA being found on the shoe, other individuals are found as well. This could be explained by secondary transfers of sloughed cellular sources of DNA. If secondary transfers are prevalent, caution should be used if DNA analysis of shoes is the only means of linking suspects to scenes.