抄録
Ultraviolet (UV) light at a wavelength of 254 nm has been used in Japan to detect latent fingerprints. However, the degradation of DNA at 254 nm UV has become a problem for short tandem repeat (STR) typing. In this study, 306 nm UV light that gives a relatively sharp fingerprint image was selected as a new light source for our imaging instrument, and its effect on STR typing was compared to that of the 254 nm UV light. Twenty microliters of saliva and 3 μl of blood were dried on glass slides and irradiated from 5-20 cm with 306 nm or 254 nm UV light for 0.5-30 min. DNA extracted from the UV-irradiated samples was quantified using real-time PCR assay and STR typing was performed. Both wavelengths reduced the amounts of DNA, as irradiated at the shorter distance or for the longer time. However, the reduction of the amount of DNA was less under the 306 nm UV light than the 254 nm. When the 306 nm UV light was irradiated from 5 cm, full STR profiles were obtained from the saliva and blood samples within 10 and 3 min, respectively. In addition, when it was irradiated from 20 cm, full STR profiles were obtained from all the samples in spite of irradiation for 30 min. It was indicated that the 306 nm UV light could be useful as a new light source. However, the use of the 306 nm UV light at a short distance or for a long time should be avoided as much as possible for STR typing.
