Role of aging in identification of DNA extracted from blood and seminal stains

Abstract

DNA investigation is playing a vital role than ever before in criminal cases as samples retrieved from crime scene may be exposed to different conditions before proceeding that can lead to degradation of DNA.One of these conditions is the aging effect. The aim of this study is to evaluate the effect of aging process on DNA extraction and typing from blood and seminal stains.The present study was done on twenty male volunteers after written consent; four ml of blood and two ml of semen were collected from the same volunteer and spotted on pieces of cotton fabric. The effect of aging (one, three and six months) extraction of DNA from blood and seminal stains were tested. DNA concentration was measured by spectrophotometer and analyzed by using gel electrophoresis. It was shown that blood and seminal stains left at room temperature for one, three and six months can be identified using presumptive tests. DNA concentration was significantly reduced in blood and seminal stains left for one, three and six months before processing. Quality of DNA was not affected by storage length and DNA fragments could be identified except for bloodstains left for six months which cannot detected by Amelogenin primer. In conclusion; DNA can be extracted from blood and seminal stains left for one, three and six months in room temperature. It is recommended to expose the samples to longer periods more than 6 months at room temperature. Different primers can be used for further research. Other types of samples can be used in further studies rather than blood and semen as saliva and teeth.