ANÁLISE GENÉTICA DOS VESTÍGIOS DE CRIMES SEXUAIS

Abstract

In Brazil sexual violence is a crime. Rape and vulnerable rape are heinous crimes. It is estimated that only 10% of rapes are recorded and the SENASP point 42.946 police incidents in 2010. Most victims are women aged below 14 years. The absence of expert evidence difficult the sentencing of the offender. In victim, exams corpus delicti of carnal knowledge and research of semen when positive do not identify the perpetrator and negativity is not a factor of no sexual assault. Genetic analysis by PCR-STR and Y identifies the presence of male DNA and the genetic profile of the perpetrator. This paper aims to analyze samples for traces of sex crimes to obtain molecular profiles of Y-STR. We selected 19 cases of sex crimes with no suspect, totaling 20 female victims aged 11 months to 81 years, which resulted in 48 samples questioned, of which 44 were subjected to differential extraction and 4 to organic extraction, totaling 92 products extraction (44 SF, 44 NSF and 4 Organic). The DNA quantitation by real-time PCR detected the presence of male DNA in 62% of the samples. Of these, 21 samples were selected and standardized to a concentration of Y-DNA 0.1 ng to 1.25 ng / PCR reaction for Y-STR. Amplification was performed for 17 joint multiplex Y-STR markers and electrophoresis capillary was preceded in genetic analyzer and the results were analyzed by programs. Of the 21 samples amplified, 12 had results for Y-STR and their haplotype been classified as full (Y-STR 17), minimum (11 Y-STR) and incomplete (absence of one or more of the Y-STR minimum haplotype) resulting 10 minimal haplotypes and complete and 02 incomplete. After comparing the minimum haplotypes and complete intra case and between their criminal cases, it was evident that the sexual assaults were committed in each case, by a single assailant, not featuring serial crimes. It is easy to recognize the importance that the Y-STR haplotype analysis assumes the sexual crimes as expert evidence, especially when it becomes the only genetic information of the offender being questioned samples obtained. The results presented in this study demonstrate the importance of being analyzed the largest number of polymorphic markers Y-STR haplotype to compose an informative, giving preference to multiplex sets that amplify multiple loci simultaneously, including polymorphic markers with products up to 200 base pairs.