RESUMO
We report here on the successful extraction of human genomic DNA from a serum sample in a forensic case. The extracted DNA was successfully used for the identification of remains presumably immersed for more than three weeks for which the only comparison sample was a 250-microL serum aliquot kept frozen in a laboratory. The analysis made it possible to identify a second victim as the daughter of the first.
Assuntos
DNA/sangue , DNA/isolamento & purificação , Medicina Legal/métodos , Genoma Humano , Adulto , Alelos , Criança , Primers do DNA , Feminino , Genótipo , Humanos , Reação em Cadeia da Polimerase , Mudanças Depois da Morte , Sequências de Repetição em TandemRESUMO
Formalin-induced DNA degradation was studied at different fixation times (3, 7, 16 and 32 days) each on 10 formalin fixed paraffin embedded tissues (FFPET) stored for 15 years at room temperature. The four different extraction protocols used in this study showed that Chelex100 extracts performed the best at 3 and 7 days of formalin fixation (DFF) (with regard to the quantity and the quality of the DNA). However, Qiamp extracts showed better results for long sized alleles, as well for single polymerase chain reaction (PCR) amplifications after 16 and 32 DFF, as for multiplex PCR at shorter fixation times. DNA degradation is expressed by the size of the amplified alleles, only 100 bp templates surviving after 32 DFF (AMG locus). Single locus amplifications (CD4 and FES/FPS alleles) performed better than multiplex PCR (ProfilerPlus), with nearly 100% positive results at 7 DFF. In both types of amplifications, the success rate decreased proportionally with the time of formalin fixation and, consequently, with the size of the required DNA template.