DNA Purification from Bloodstains and Buccal Cells/Saliva on FTA Cards.

FTA cards enable efficient, long-term storage of blood and buccal cells/saliva samples for future forensic DNA analysis; these are typically collected as known reference samples, as opposed to evidentiary, crime scene samples. Upon contact with the FTA card, cells are lysed and the DNA is immobilized. Different FTA cards are available and have been specially formulated based on sample type: bloodstains are added to the traditional FTA Card, while colorless sources (e.g., buccal cells/saliva) are added to the FTA Indicating Card. The main difference between these cards is the presence of a pink dye embedded in the indicating cards that becomes white when exposed to colorless fluids, like saliva; this aids in location confirmation of the stain for future sampling. Although DNA can be eluted/extracted from FTA punches using various methods or, alternatively, direct STR amplification from unpurified punches can be performed, the protocol herein describes a simple purification method for bloodstained punches from FTA Cards as well as buccal/saliva-stained punches from FTA Indicating Cards. Following this purification, STR amplification can be performed via the "punch-in" method.