Optimized pH method for DNA elution from buccal cells collected in whatman FTA® cards

DNA is the most accessible biologic material for obtaining information from the human genome because of its molecular stability and its presence in every nucleated cell. Currently, single nucleotide polymorphism genotyping and DNA methylation are the main DNA- based approaches to deriving genomic and epigenomic disease biomarkers. Upon the discontinuation of the Schleicher & Schuell IsoCode (R) product ( Dassel, Germany), which was a treated paper system to elute DNA from several biologic sources for polymerase chain reaction ( PCR) analysis, a high- yielding DNA elution method was imperative. We describe here an improved procedure of the not fully validated Whatman pH- based elution protocol. Our DNA elution procedure from buccal cells collected in Whatman FTA (R) cards ( Whatman Inc., Florham Park, NJ) yielded approximately 4 mu g of DNA from a 6- mm FTA (R) card punch and was successfully applied for HLA- DQB1 genotyping. The genotypes showed complete concordance with data obtained from blood of the same subjects. The achieved high DNA yield from buccal cells suggests a potential cost- effective tool for genomic and epigenomic disease biomarkers development.