Effect of storage of blood samples on DNA yield, quality and fingerprinting: a forensic approach

Various storage treatments on human blood samples have been described with respect to DNA yield, quality and fingerprinting. Blood samples were stored at room temperature, 4 degrees C, -20 degrees C and -70 degrees C for different duration varying from 1, 2, 4 and 8 weeks with or without anticoagulant/preservative (EDTA or Heparin). DNA was isolated from these stored samples, quantitated by spectrophotometry and subjected to DNA fingerprinting using a human alphoid satellite DNA sequence (TRF 5.6) and a 33 mer oligonucleotide (O-chi-1) as probes. The polymorphic DNA bands were apparent between 2 to 9 kb size range and the fingerprints were individual-specific. Our results suggest that higher amount of genomic DNA can be recovered from blood samples stored at temperatures 4 degrees C or below in the presence of EDTA or heparin.