Quality and quantity of saliva DNA obtained from the self-administrated oragene method--a pilot study on the cohort of Swedish men.

Self-collection of saliva has the potential to provide molecular epidemiologic studies with DNA in a user-friendly way. We evaluated the new Oragene saliva collection method and requested saliva samples by mail from 611 men (ages 53-87 years). We obtained a response rate of, on average, 80% [varying from 89% (ages 67-71 years) to 71% (ages 77-87 years)]. DNA was extracted from 90 randomly selected samples, and its usefulness was evaluated with respect to quality, quantity, and whole-genome amplification (WGA). Visual inspection of DNA on agarose gels showed high molecular weight DNA (>23 kb) and no degradation. Total DNA yield measured with PicoGreen ranged from 1.2 to 169.7 mug, with a mean of 40.3 mug (SD, 36.5 mug) and a median of 29.4 mug. Human DNA yield was estimated by real-time PCR of the human prothrombin gene to account for 68% (SD, 20%) of total DNA. We did WGA on 81 saliva DNA samples by using the GenomiPhi DNA kit and genotyped both saliva DNA and WGA DNA for 10 single-nucleotide polymorphisms randomly selected from the human genome. Overall genotyping success rate was 96% for saliva DNA and 95% for WGA DNA; 79% of saliva DNA samples and 79% of WGA DNA samples were successfully genotyped for all 10 single-nucleotide polymorphisms. For the 10 specific assays, the success rates ranged between 88% and 100%. Almost complete genotypic concordance (99.7%) was observed between saliva DNA and WGA DNA. In conclusion, Oragene saliva DNA in this study collected from men is of high quality and can be used as an alternative to blood DNA in molecular epidemiologic studies.