Grading a rape case followed by death from the study of autosomal STRs and STRs of the Y chromosome—Case study

Two women were found dead inside a residence. Choke causes death in one that had been naked in a bed and contusion injury in another that was found on a sofa. Were received samples of vaginal and anal swabs of the two victims of homicide with suspected of having suffered sexual violence. References also received samples of two victims and a suspect. We performed genetic analysis for identification of samples from the meeting of any possibility of overlap between patterns and profiles of sequences of deoxyribonucleic acid (DNA) based on genetic relationship between those involved. The reference samples were subjected to the procedure of extraction of nuclear DNA by Chelex method and the swabs samples by differential extraction. For all the samples were performed for amplification of STRs loci and autosomal STRs of chromosome Y. The profiles of DNA sequences were obtained by the Polymerase Chain Reaction (PCR), using sequences starting with marked substances emitting fluorescence detected by reading the optical laser in 3100 Avant automatic sequencer from Applied Biosystems. The information of consecutive loci of Short Repeats or STRs of autosomal chromosomes and the Y chromosome was obtained using the systems or products sold in multilocus, methodologies recommended by the supplier and valid for analysis of DNA. We used the multilocus Identifiler and YFiler system of Applied Biosystems to the amplification of samples. The validation of results has shown a genetic profile in male anal secretion of the victims with a complete coincidence with the suspect.