[Buccal swab: a convenient source of DNA for analysis of IL-1 gene polymorphisms]

PCR-RFLP based techniques have become standard procedures for gene polymorphism screening. Peripheral venous blood is currently the most commonly employed source of DNA for human genome analysis. However, it has many practical disadvantage and inherent limitations to use blood as DNA source. Blood sampling is invasive, painful and involves a potential risk of contamination with hepatitis. The classic procedure to extract genomic DNA from whole blood is phenol/chloroform technique, which is relative complicated and time consuming. Therefore, this study was performed to try an alternative instead of using blood as DNA source for gene polymorphism analysis.

Four methods were employed to obtain DNA from the same subject including DNA from venous blood through phenol/chloroform extraction, DNA from dried blood spot through Chelex 100 technique, DNA from buccal swab through Chelex 100 technique and the dried blood spot directly as DNA template for PCR. Then, these various forms of DNA were used in PCR RFLP procedure to analyze IL-1 gene polymorphisms, and their specificity and sensitivity were evaluated.

Our results indicate that both the buccal swab and the blood based assays reached complete concordance in typing the IL-1 gene polymorphisms, while the Chelex 100 procedure for extracting DNA from buccal swab is much simpler and more rapid. It is non-invasive to get buccal swab. The amount of DNA obtained through one buccal swab is 63.8 micrograms +/- 18.7 micrograms, which is enough for 10 PCR reactions.

Buccal swab appears to be an excellent source of DNA for detection of polymorphisms of human IL-1 gene.