EXTRAÇÃO DE DNA DE IMPRESSÕES DIGITAIS LATENTES DEPOSITADAS EM DIFERENTES SUPORTES E REVELADAS COM NINIDRINA E PÓ PRETO.

Abstract

The importance of scientific proof for the current Brazilian justice system is notorious. Article 158 of the CPC provides that when the offense is a trace essential examination of the corpus delicti. But many fingerprints arriving in section showdown Police Technician - Scientific Goiás, do not present conditions for analysis are blurred or incomplete, and thus unusable. The possibility of extracting DNA of these appears as an option in criminal investigations. The present study detected by light microscopy, scaly epidermal cells in 98% of the fifty sheets containing fingerprints subjected to Leishman stain, and the amount varied from fifteen to seven hundred and seventy cells per slide. After DNA extraction sixty-nine samples, deposited on five different media (aluminum, wood, paper, plastic and glass) were obtained concentrations ranging from 0.3 ng / uL to 25.4 ng / uL. Analyzing the concentrations of each surface separately observed that wood was the one with the highest average concentration of DNA (10.67 ng / uL), while paper and plastic had equal means and the lowest (5.92 ng / uL) . Comparing the media by student t test, we found three statistically significant analysis, the largest difference was observed between the surfaces of wood and paper (p = 0.001). When extracting DNA prints developed with ninhydrin or impregnated by black powder, concentration obtained in 70% of samples with ninhydrin and 60% of samples with dust. This study corroborates several studies have shown that it is possible to extract DNA from surfaces that have been touched by the hands of just one person. Our experiments also showed obtaining a higher concentration in the porous surfaces in relation to smooth surfaces and that using ninhydrin and black powder also allow the extraction of said genetic material.