Evaluation of tolerable time and temperature during storage of saliva sample for DNA isolation and subsequent amplification of CYP1A2 partial gene

Abstract

Saliva is an excellent source of intact genomic DNA for diverse applications, favoured due to its collection and great DNA quality. Buccal cells in the saliva can provide the DNA for subsequent analyses, yet found to degrade in improper conditions, affecting the final DNA result. Coupling saliva with a stabilization buffer can preserve the salivary DNA during transport and storage. Previously developed buffer has been tested to suit the requirements to prolong the storage time for saliva samples. However, the tolerable limit condition for the buffered saliva samples has not been identified. Here we show that storing the saliva in different temperatures overtime periods did not significantly affect DNA concentration and purity. No significant differences were found in concentration and purity between samples stored in different temperatures (4°C, 25°C, 37°C) and different time periods (2h, 4h, 6h, 8h). Samples from all storage conditions were able to be amplified by using CYP1A2 primers. The result suggests that the buffer and the methods used in this study can help the saliva withstand different storage temperatures as long as 8 hours without any significant decrease in quality. This study aimed to widen the opportunity of using saliva as a source of human DNA. This study had proven that the methods used are adequate to process the saliva samples for subsequent PCR analysis. Further development of the study may include quantifying human DNA and bacterial DNA and the improvement of purity.