DNA from Fingerprints: The Effect of Deposition Pressure on the Size and Quality of Latent Fingermarks and On the Efficacy of STR Profiling in Forensic Identification

Ido Hefetz, DIFS, Israel Police , Jerusalem, Israel
Marina Faerman, DIFS, Israel Police , Jerusalem, Israel
Michal Horowitz, DIFS, Israel Police , Jerusalem, Israel
Yossi Almog, The Hebrew University, Jerusalem, Israel


The discovery that DNA can be extracted from fingermarks (“touch DNA”) greatly improved the success rate of serious crime investigations and also enabled a much more efficient search for invisible DNA through the detection of latent fingermarks. In our recent study on touch DNA we tried to learn some basic facts about the effect of deposition pressure on the quality of the developed fingermarks and the extracted DNA.  A simple device which allows taking latent fingermarks from volunteers under controlled pressures had been designed and constructed and 900 fingermarks have been collected from 20 volunteers on 3 different surfaces. The following observations have been made:

1. No correlation was found between the qualities of the developed fingermarks and the DNA extracted from them. It was noticed that a low quality fingerprint might yield sufficient amount of DNA for forensic analysis, quantitatively and qualitatively.


2. On two of the examined surfaces, glass and polythene, the quality of the developed fingermarks increased with the deposition pressure up to 3 kg and decreased at a higher pressure (10kg). On the third surface, paper, the quality kept increasing with deposition pressure up to 10 kg.


3. On all three surfaces increasing deposition pressure, ranging from 0.1 kg to 10 kg, resulted in higher DNA concentration, larger numbers of STR's amplified and of comparable DNA profiles.