[Isolation of free DNA from archived serum samples suitable for molecular genetic studies]

Collected and archived serum samples could be important sources for genetic studies, once DNA suitable for molecular genetic studies could be obtained from them.

DNA was isolated from 54 archived sera samples, collected previously from the participants of a Hungarian allergy study, with commercially available isolation kit. The authors have determined the concentration of the isolated DNA (81.88 +/- 52.36 ng/ml) and the size of the isolated fragments was estimated using semiquantitative real-time PCR. Two primers were used producing two different fragment size, for the phospholipase 2A and the actin beta genes, and melting curve analyses was performed as quality control.

The concentration of the phospholipase 2A product was 2.9798 +/- 5.4454 microg/microl and the actin beta gene was 0.0015 +/- 0.0011 microg/microl. The melting curve analysis served as a quality control for the determination of the size of PCR products. In the case of the phospholipase 2A all samples produced the 133 bp PCR fragments, except one, while in the case of actin beta gene only six sample showed the expected 178 bp product, all the others samples had smaller fragments.

These results confirm the suitability of the DNA isolated from archived sera samples for further molecular biological studies (SNP analysis, mutation detection) and give an estimate for the product size of the isolated DNA. Sera samples have been collected years ago can be a good source of genetic information on different diseases.