Application of DNA Polymorphisms to the Forensic Examination of Dried Blood Stains

We have examined the possibility of using DNA purified from dried blood stains for the analysis of restriction fragment length polymorphisms. High molecular weight DNA was recovered from blood dried on cotton cloth, aged from one day to three years. These DNA samples were digested with restriction endonucleases, separated by agarose gel electrophoresis and hybridized to recombinant DNA probes that recognize two different highly polymorphic DNA sequences. A set of controlled samples was aged at room temperature for up to 28 days. The polymorphic DNA pattern observed with each probe remained the same at all time points. The patterns of DNA polymorphisms observed in the two and three year old dried blood stains was consistent with patterns observed in the general population. These results indicate that DNA recovered from dried blood stains can be used for identification purposes.