RESUMO
BACKGROUND: Obtaining high quality genomic DNA safely and economically is vital for diverse studies of large populations aimed at evaluating the role of genetic factors in susceptibility to disease. AIM: This study was to test a protocol for the extraction of high quality genomic DNA from saliva samples obtained with mouthwash and taken from patients with periodontal disease. METHODS: Saliva samples were taken from 60 patients and then stored at room temperature. DNA extraction was carried out at distinct post-sampling times (10, 20 and 30 days). Evaluation of genomic DNA was performed with spectrophotometry, electrophoresis, and PCR genotyping and sequencing. RESULTS: The greatest concentration of DNA obtained was 352 µg at 10 days post-sampling, followed by 121.025 µg and 19.59 µg at 20 and 30 days, respectively. When determining the purity of DNA with the spectrophotometric ratio of 260/230, the relations of 1.20, 1.40 and 0.781 were obtained for 10, 20 and 30 days, respectively. In all samples, it was possible to amplify the product of 485 bp and the sequence of the amplicons showed 95% similarity to the reference sequence. CONCLUSION: The present protocol represents an easy, safe and economical technique for obtaining high quality genomic DNA.
