Ultraviolet (UV) light at a wavelength of 254 nm has been used in Japan to detect latentˆngerprints. 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 sharpˆngerprint image was selected as a new light source for our imaging instrument, and its eŠect on STR typing was compared to that of the 254 nm UV light. Twenty microliters of saliva and 3 ml 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 quantiˆed 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 proˆles 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 proˆles 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.

We examined whether powders and transfer sheets for detecting latentˆnger-prints aŠect DNA extraction and subsequent short tandem repeat (STR) typing adversely. To examine the powders, saliva and blood samples were smeared and dried on glass slides, and then adhered with aluminum powder, black powder, magnetic powder (NBS), magnetic powder (Sirche), SP black and indigo. To examine transfer sheets, saliva and blood samples were smeared and dried on gelatin sheets, JP sheet and Lifter. DNA was extracted from the powder-adhered samples or the samples on the sheets, quantiˆed by a real-time PCR assay, and the STR typing was performed using the Identiˆler kit.The aluminum powder and the SP black aŠected the storage of the DNA solution, and required a centrifugation step to remove the powders, or required TE -4 buŠer for DNA elution instead of water. The magnetic powder (NBS) made the DNA extraction impossible, when an excessive amount of the powder was adhered. However, the DNA extraction was possible, when most of the powder was removed with a magnetic brush. The black powder, the magnetic powder (Sirche) and the indigo gave enough DNA concentration and full STR proˆles. All the transfer sheets did not give adverse eŠects.As simulated casework samples, 20ˆngerprints deposited on a glass slide in two

Ninhydrin and its analogues are wildly used to detect latentˆngerprints on porous materials. When the contrast of ninhydrin-developedˆngerprints is not su‹cient, indium chloride (InCl 3 ) treatment has been used to improve their images. For non-porous materials, polycyanoacrylate p-dimethylaminobenzaldehyde (DMAB) method and tris thienyl europium chelate (T.TEC) method have recently been developed in Japan. In this study, we examined the eŠects of these latentˆnger-print detection methods on short tandem repeat (STR) typing. Saliva and blood samples were attached to and dried on copy paper for the experiments of the ninhydrin, 1,2 indanedione, and 1,8 diaza‰uoren 9 one (DFO). Saliva and blood samples were also smeared and dried on glass slides for the experiments of the polycyanoacrylate DMAB, and the T.TEC. DNA was extracted from the samples, quantied by a real-time PCR assay, and the STR typing was performed using the Identiˆl-er kit.Various ninhydrin solutions including the acetone and acetic acid solution tended not to reduce the DNA concentrations, and provided full STR proˆles. Heating by putting an iron directly on the samples remarkably reduced the DNA concentrations for 30 seconds. It was recommended that direct-heating be prohibited and that the