AbstractSaliva may be found on victims of several violent crimes and it has been shown that it can also be potentially recovered and typed from bite marks, cigarette butts, postage stamps, envelopes and other objects. The double swab technique has been shown to increase the amount of salivary DNA recovered from skin when compared to other methods. Aim and objective: To recover DNA from saliva deposited on human skin by double swab method and amplification of microsatellites and minisatellites from the recovered DNA. Materials and method: Saliva from five volunteers was deposited on human skin and recovered using the double swab technique. DNA extraction was done using phenol chloroform method and PCR was used for amplification of 5 genes {Amelogenin (AMG), von Willebrand factor (vWF), F13 and D4S and Apolipoprotein (APO B)}. DNA was obtained from blood and direct salivary samples of the same volunteers and was used to compare the gene amplifications obtained by double swab technique. Results: We found that using the DNA recovered from double swab technique F13 could be amplified in all 5 samples (100%) saliva samples deposited on skin, AMG, D4S and APO B genes could be amplified in 80%, 60% and 40% samples respectively whereas vWF gene failed to amplify in any of the sample. DNA amplified from all five samples of double swab technique matched positively with DNA obtained from saliva and blood. Conclusion: Double swab technique can be used for isolating DNA from deposited saliva samples for the purpose of forensic study though the technique needs to be refined.
Key words: Short Tandem Repeats (STR), Variable Number Tandem Repeats (VNTR), AMG, F13, VWF, D4S and APO B.