Evaluation of DNA quality obtained from stored human saliva and its applicability in forensic identification in Forensic Dentistry / Avaliação da qualidade do DNA obtido de saliva humana armazenada e sua aplicabilidade na identificação forense em odontologia legal

AUTOR(ES)
DATA DE PUBLICAÇÃO

2009

RESUMO

The saliva can be used as efficient DNA source for human identification techniques in which they are accepted as forensic proof, being the superlative professionals opinion for the sentence formulation. This material can be collected in a painless and noninvasive way and it is used even when stored in different conditions. This paper aims at evaluating DNA quality obtained from stored human saliva and its applicability in people identification. Saliva samples from n=100 research subjects were analyzed. They were collected in two ways: in natura and swab. The saliva was stored at the temperature of -20°C. After 7 days, the first phase was performed, when the DNA was extracted from the 200 saliva samples using the InstaGene resin (Bio-Rad Laboratories, Inc., Hercules, CA, USA) and, subsequently, submitted to PCR and electrophoresis. After 180 days of the saliva storage, the same technique used in the first phase was repeated; however, in only 20 samples, selected at random from the total of 100 ones collected from mouth swab. The results of the first phase indicated that the DNA was successfully extracted in 96% of the reactions performed for the 200 saliva samples. This fact was also observed when the separate saliva samples in natura (94%) and swab (98%) were analyzed. In addition, there were no statistically significant differences in the extraction of the DNA between the two ways used for collecting saliva. In the second phase, the target gene detection was possible in the 20 samples analyzed (100%). Subsequently, the SIX3-2 gene was tested in the samples with the objective of deepening the salivary DNA analysis as close as the standard required in an identification process. Also, the digestion of the PCR product with the enzyme of MbO1 restriction was performed to evaluate the polymorphism of the ADRA- 2 gene. The results showed that the DNA quantity and quality from the mouth swab saliva, as well as the techniques applied are suitable for the forensic analysis of DNA. Therefore, the human saliva is very useful as DNA source and can be stored in ideal temperature and conditions for further analysis.

ASSUNTO(S)

criminologia molecular biology odontologia legal dna medicina legal criminology cariologia molecular identificação humana saliva human identification dna saliva forensic medicine forensic dentristry

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