Evaluation of buccal cell collection protocols for genetic susceptibility studies

Buccal cells are increasingly used as a source of quality DNA to improve pa rticipation rates in molecular studies. Here, three buccal cell collection protocols were compared to determine factors affecting the yield of cells, total DNA per sample, and DNA yield per cell. In addition, kinetic quantita tive polymerase chain reaction (PCR) (TaqMan(TM)) was used to quantify huma n DNA available for PCR. The method of collection used influenced the overa ll DNA yield per sample. The collection buffer used influenced the number o f cells but not the overall DNA yield per sample. Repeated freezing and tha wing did not affect overall DNA yield per sample, DNA yield per cell, or th e total number of cells collected. Mouthwashes had the highest DNA yield pe r sample (20.8 mug) compared with cytobrush samples (1.9 mug from three cyt obrushes) and tongue depressors (0.8 mug from three tongue depressors). How ever, mouthwash samples may contain significant non-human DNA and other con taminants that could interfere with some molecular studies. Spectrometry gr ossly overestimated the total DNA recovered from mouthwash samples compared with fluorometry or quantitative PCR.