DNA analysis has several benefits. Only a small amount of tissue is required for DNA analysis, and it can be used for samples that are too old for the identification of many protein genetic markers. In addition, it is useful for analyzing the mixed stains that often occur in sexual assault cases. Moreover, a laboratory can easily check the results from another laboratory, and a database of DNA patterns can be established to aid further investigations. Limitations of DNA analysis include the time it requires, its cost, the repetitive procedures involved, and the small number of forensic serologists trained in the technique. 3 reference notes.