Amplification of HLA-DQA1 gene from bloodstains by polymerase chain reaction

The DNA typing of HLA-DQA1 from bloodstains is described. Although amplification of DNA from bloodstains was sometimes difficult, the addition of BSA to the PCR medium induced good amplification. When a very limited amount (2 mm2, equivalent to 0.5 microliter blood) of bloodstain was analysed, the amplification was difficult. However, the addition of salmon sperm DNA to the DNA isolation medium, in the amount of 1 microgram per tube, yielded sufficient PCR products even when such a small amount of extract was analysed. DNA from bloodstains aged up to one year could be sufficiently amplified, if salmon sperm DNA was added to the DNA isolation medium, and BSA to the PCR medium.