Analysis of DNA in minute volumes of blood from stains and crusts

As the first step, the locus D1S80 was amplified by the polymerase chain reaction technique from genomic DNA extracted from artificial bloodstains and crusts with different amount of blood (32 microl, 16 microl, 8 microl, 4 microl, 2 microl, and 1 microl). In all samples of bloodstains and crusts, identification by DNA analysis was possible. As the second step, the locus HLA-DQA1 was amplified from genomic DNA extracted from diluted blood samples (640, 320, 160, 80, 40, 20, 10, and 5 leukocytes). DNA amplification was possible in diluted blood samples with at least 10 leukocytes. Considering the conditions in which the present study was carried out, it was possible to conclude that 1 microl of bloodstains or crusts was enough for identification. It was also concluded that five leukocytes are not enough material to render consistent DNA identification.