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Open Access Highly Accessed Research article

Quality of DNA extracted from saliva samples collected with the Oragene™ DNA self-collection kit

Ana P Nunes1*, Isabel O Oliveira2, Betânia R Santos3, Cristini Millech4, Liziane P Silva5, David A González6, Pedro C Hallal7, Ana M B Menezes7, Cora L Araújo7 and Fernando C Barros7

Author Affiliations

1 Histology Laboratory, Morphology Department, Institute of Biology, Universidade Federal de Pelotas (UFPel), Pelotas, Brazil

2 Physiology Department, Institute of Biology, Universidade Federal de Pelotas (UFPel), Pelotas, Brazil

3 Academic Doctoral Biological Sciences, Physiology Department, Institute of Health Basic Sciences, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil

4 BS in Biological Sciences (UFPel), Pelotas, Brazil

5 Academic of Postgraduate in Biotechnology (UFPel), Pelotas, Brazil

6 Nutrition Department, Universidade Federal de Santa Catarina, Florianópolis, Santa Catarina, Brazil

7 Postgraduate in Epidemiology (UFPel), Pelotas, Brazil

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BMC Medical Research Methodology 2012, 12:65  doi:10.1186/1471-2288-12-65

Published: 4 May 2012

Abstract

Background

Large epidemiological studies in DNA biobanks have increasingly used less invasive methods for obtaining DNA samples, such as saliva collection. Although lower amounts of DNA are obtained as compared with blood collection, this method has been widely used because of its more simple logistics and increased response rate. The present study aimed to verify whether a storage time of 8 months decreases the quality of DNA from collected samples.

Methods

Saliva samples were collected with an OrageneTM DNA Self-Collection Kit from 4,110 subjects aged 14–15 years. The samples were processed in two aliquots with an 8-month interval between them. Quantitative and qualitative evaluations were carried out in 20% of the samples by spectrophotometry and genotyping. Descriptive analyses and paired t-tests were performed.

Results

The mean volume of saliva collected was 2.2 mL per subject, yielding on average 184.8 μg DNA per kit. Most samples showed a Ratio of OD differences (RAT) between 1.6 and 1.8 in the qualitative evaluation. The evaluation of DNA quality by TaqMan®, High Resolution Melting (HRM), and restriction fragment length polymorphism-PCR (RFLP-PCR) showed a rate of success of up to 98% of the samples. The sample store time did not reduce either the quantity or quality of DNA extracted with the Oragene kit.

Conclusion

The study results showed that a storage period of 8 months at room temperature did not reduce the quality of the DNA obtained. In addition, the use of the Oragene kit during fieldwork in large population-based studies allows for DNA of high quantity and high quality.